fundamental accounitng assumptions

Listen dude ,

u r really confused .. as per AS-1 :- Disclosure is needed for all the departures from accounting standards , change in accounting policy and non following of basic accounting principles and assumptions

accounting method to be followed is mentioned by the statue for which accounts are to be prepared.

if someone is preparing accounts under Income Tax law  , then as per SEC. 145 it is mandatory either to follow CASH or MErcantile system

similarly if u preparing for COmanies ACt, refer sec 211