in purchase of software u need to deduct tax u/s. 194 J under head fees for professional and technical services.
but disallowance is subject to capitalise or revenue. many judicial decisions are clearified that software may be revenue expenditure, in this situation entire amount will be disallowed.
if it is capitlised there is a drafting error in law, in absense of any section for disallowance for depriciation u can claim depriciation also.
In this scenario disallowance is governed by 40 series and in this series section for diallowance of depriciation is not added by department.
I hope this is useful to u.