Hi David,
good summary of the necessary steps. I set it up similar, yet without the contracts.

I assigned certain working hours for each employee individually based on the current real work contract, e.g. 8 hours Monday to Friday (40 h/week) or 6 hours Monday to Thursday (24 h/week with Fridays off).

After this the employees entered their attendences every day. Extra hour were calculated and in the time sheets the recorded times were compared to the working hours per day additionally - great so far!

In addition I set up public holiday in the Time Off app. By doing so time sheets were automatically generated for those days with the employees individual working hours for those days. This happens for all public holidays also in advance. If you have entered all public holiday for the upcoming three years, the time sheets will instantly be generated for all those days - also great so far!

The problems started when the working hours of a particular employee are changed, e.g. reduced from initially 40 h/week to now 30 h/week.

Problem 1: The initally generated time sheets for publich holiday will not be updated! They still kepp the old working hours.

Problem 2: In the time sheets the difference between the actually recorded times the new working hours will be applied even for the past!

Problem 3: The extra hours in the past do not seem to be affected in this way. The extra hours are always calcualted based on the acutal recorded attendences and the working hour valid at the time of attendence entries. But if the entries are modified after the change of the working hours, the extra hours for this particular working day will be based on the new working hours.

I am looking for a way, to apply different working times (for time sheets and extra hours) at different time.

I tried to use the payroll and contracts. I generated two contracts for the same employee and set the start and end dates so, that they were after each other (contract 1 from 01.01.2023 - 30.06.2023, contract 2 starting froom 01.07.2023 without end.) But this did not solve the problem.

Is there any way to set Odoo up in way to correctly deal with modified working hours?

Hello Benjamin,

Handling modified working hours in Odoo's HR Attendance and HR Timesheet modules can be a bit tricky, but it's certainly possible with some customization and configuration. Here are some suggestions to address the issues you've encountered:

Problem 1: Time Sheets for Public Holidays Not Updated

This issue arises because the time sheets for public holidays are generated in advance based on the employee's initial working hours. To address this problem, you can create a custom module or script that updates the time sheets for public holidays when an employee's working hours change.

Here's a high-level approach:

Create a custom Odoo module or script that listens for changes in an employee's working hours.

When the working hours are modified, trigger an event or action that recalculates and updates the time sheets for upcoming public holidays for that employee. This may involve deleting the old time sheets and generating new ones based on the updated working hours.

You'll need to use Odoo's API to interact with time sheet data and make the necessary updates programmatically.

Problem 2: Retroactive Calculation of Differences

To handle the retroactive calculation of differences between recorded times and new working hours, you may need to implement a similar custom solution as described above. When working hours change, you should have a mechanism in place to recalculate past time sheets based on the working hours applicable at the time of each attendance entry. This will require scripting and Odoo API usage.

Problem 3: Extra Hours Calculation

The calculation of extra hours is based on recorded attendance and the working hours valid at the time of attendance entries. To ensure that extra hours calculations are accurate when working hours change, you'll need to implement logic to recalculate extra hours for past attendance entries based on the historical working hours for each entry.

In summary, addressing these issues may require custom development and scripting within Odoo to ensure that time sheets and extra hours are correctly calculated when working hours change. You'll need to work with Odoo's API and possibly create custom modules to achieve the desired functionality. Depending on the complexity of your requirements, you may also consider consulting with Odoo experts or developers to help implement these customizations effectively.

Answering your final question:

Odoo is a flexible and customizable platform, and you can set it up to handle modified working hours to some extent. While Odoo's standard functionality may not fully address all the complexities of changing working hours, you can use some of its built-in features and additional configurations to make the system work for your needs. Here's how you can set up Odoo to deal with modified working hours:

Use Contracts: As you've mentioned, Odoo's contract feature is designed to manage employee working hours, so make sure to utilize it. When an employee's working hours change, you can update their contract with the new hours.

Contract Start and End Dates: When creating or editing a contract, set the start and end dates accurately to reflect when the new working hours take effect. For example, if an employee's working hours change from January 1, 2023, set the end date of their old contract to December 31, 2022, and the start date of their new contract to January 1, 2023.

Timesheet Entries: Odoo's timesheet entries are linked to contracts. When an employee logs their working hours, the system should consider the contract that is active during that period. So, if an employee logs hours for January 2023, it should use the working hours specified in the contract active at that time.

Regularly Review and Update Contracts: Ensure that HR or relevant personnel regularly review and update contracts as working hour changes occur. This may require a manual process, but it's essential to keep contracts up to date.

Public Holidays: For public holidays, you may need to create and manage contracts that cover these specific dates separately. If an employee's working hours change around public holidays, you can create a contract for the specific period that includes the holiday with the correct working hours.

Communication: Maintain clear communication with employees regarding changes in working hours and contracts. This helps employees understand which contract applies to them during specific periods.

Reporting and Analysis: When analyzing timesheet data or generating reports, ensure that you select the appropriate contract filter to get accurate results for the relevant working hours.

While these steps can help you set up Odoo to handle modified working hours, it's important to note that handling complex scenarios, retroactive calculations, and automated updates of historical data may require custom development or integration with external tools or scripts. Depending on your specific requirements, you may need to work with Odoo developers or consultants to tailor the system to your exact needs.