@equinox123
The information i guess you provided is insufficient for people to help,
Since you say you flown in C-152 through out you training, i Presume you have a SE FAA CPL on C-152, and getting endorsed on a C-172 shall not be a problem, since if you are doing your recency, which is about 15hr, and you do all of that in C-172, and give a check with a respective CFI the you shall be good to go.
On the other hand if you have a FAA ME CPL, and you shall prefer to Take a SE CPL then also you have fly for 20-24hr in India to complete recency and related flying so still you shall be good.
I think the whole idea behind DGCA endorsing you on a C-172 or any new type of airplane is that they wanted to make see that you have at least flown for 10hr on that specific aircraft.
@anirudh_rao
in case 2 don't forget that the 6hr flying for skill test on a PA 34-200 is only applicable if you have already flown for at least 10hr on that particular aircraft (Endorsed on your FAA/forgein licence), they(DGCA) actually made it clear on this
http://dgca.nic.in/circular/FCL1_2012.pdf under Appendix 1 8th point.
And in case 2 the 15hr is also not possible, since when you approach a flight school, he shall first do some dual checks and also 4 hr of instrument will be dual, in order for you to be released a solo for PIC time building. so don't forget the cost involved for that as well.