Product onchange in account invoice line doesn't consider the product pricelist. The unit price is not changing according to the pricelist. Is this a bug ?

def product_id_change(self, cr, uid, ids, product, uom_id, qty=0, name='', type='out_invoice', partner_id=False, fposition_id=False, price_unit=False, currency_id=False, context=None, company_id=None):
    if context is None:
        context = {}
    company_id = company_id if company_id != None else context.get('company_id',False)
    context = dict(context)
    context.update({'company_id': company_id, 'force_company': company_id})
    if not partner_id:
        raise osv.except_osv(_('No Partner Defined !'),_("You must first select a partner !") )
    if not product:
        if type in ('in_invoice', 'in_refund'):
            return {'value': {}, 'domain':{'product_uom':[]}}
        else:
            return {'value': {'price_unit': 0.0}, 'domain':{'product_uom':[]}}
    part = self.pool.get('res.partner').browse(cr, uid, partner_id, context=context)
    fpos_obj = self.pool.get('account.fiscal.position')
    fpos = fposition_id and fpos_obj.browse(cr, uid, fposition_id, context=context) or False

    if part.lang:
        context.update({'lang': part.lang})
    result = {}
    res = self.pool.get('product.product').browse(cr, uid, product, context=context)

    if type in ('out_invoice','out_refund'):
        a = res.property_account_income.id
        if not a:
            a = res.categ_id.property_account_income_categ.id
    else:
        a = res.property_account_expense.id
        if not a:
            a = res.categ_id.property_account_expense_categ.id
    a = fpos_obj.map_account(cr, uid, fpos, a)
    if a:
        result['account_id'] = a

    if type in ('out_invoice', 'out_refund'):
        taxes = res.taxes_id and res.taxes_id or (a and self.pool.get('account.account').browse(cr, uid, a, context=context).tax_ids or False)
    else:
        taxes = res.supplier_taxes_id and res.supplier_taxes_id or (a and self.pool.get('account.account').browse(cr, uid, a, context=context).tax_ids or False)
    tax_id = fpos_obj.map_tax(cr, uid, fpos, taxes)

    if type in ('in_invoice', 'in_refund'):
        result.update( {'price_unit': price_unit or res.standard_price,'invoice_line_tax_id': tax_id} )
    else:
        result.update({'price_unit': res.list_price, 'invoice_line_tax_id': tax_id})
    result['name'] = res.partner_ref

    result['uos_id'] = uom_id or res.uom_id.id
    if res.description:
        result['name'] += '\n'+res.description

    domain = {'uos_id':[('category_id','=',res.uom_id.category_id.id)]}

    res_final = {'value':result, 'domain':domain}

    if not company_id or not currency_id:
        return res_final

    company = self.pool.get('res.company').browse(cr, uid, company_id, context=context)
    currency = self.pool.get('res.currency').browse(cr, uid, currency_id, context=context)

    if company.currency_id.id != currency.id:
        if type in ('in_invoice', 'in_refund'):
            res_final['value']['price_unit'] = res.standard_price
        new_price = res_final['value']['price_unit'] * currency.rate
        res_final['value']['price_unit'] = new_price

    if result['uos_id'] and result['uos_id'] != res.uom_id.id:
        selected_uom = self.pool.get('product.uom').browse(cr, uid, result['uos_id'], context=context)
        new_price = self.pool.get('product.uom')._compute_price(cr, uid, res.uom_id.id, res_final['value']['price_unit'], result['uos_id'])
        res_final['value']['price_unit'] = new_price
    return res_final