I am attchaning improved patch with consideration of company_id on fiscal year. So now check will see if the both the fiscal year (old and new) has same company and with same/in between start and end dates it does not allow to create it. But if the companies are different then we can create fiscalyears with same start and end dates as accepted.
Can you please check this patch ?
Note: Without demo data it allows to create Accounting Charts But if we create db with demo data (In demo data we have already created fiscalyear) it does not allow us to configure Account charts.