Use of prescribed forms.

(a) A taxpayer shall not be excused from filing a declaration of estimated tax under this regulation by reason of the fact that no return form (RIT-PA40ES) has been furnished to him. Copies of the prescribed return forms so far as possible will be regularly furnished taxpayers by the Department without application therefor. Taxpayers not so supplied with the proper forms should make application therefor to the Department in ample time to have the declaration prepared, verified, and filed on or before the due date.

(b) If, through no fault of the taxpayer, the prescribed form is not available, a signed statement by the taxpayer disclosing the amount of estimated tax due together with remittance thereof, if filed within the prescribed time, may be accepted as a tentative declaration, so as to relieve the taxpayer from liability for additions, if without unnecessary delay such tentative declaration is supplemented by a declaration made on the proper form.