Does CPT done in previous Masters count towards CPT limit for OPT eligibility after current Masters

I have a double Masters. I completed Masters in Engineering Management in March 2013(and did not file for OPT) and will soon fininsh Masters in Computer Science. I am planning to apply for OPT in the coming days. During both Masters degrees, I have used CPT as follows:

2.5 Months - 1st Masters

6 Months - 2nd Masters

Now I understand that using more that 11 months 29 days makes you ineligible for OPT. My question is will the 2.5 months of CPT done in my 1st Masters degree count toward that 11 month 29 day limit?

No, they are not cumulative. You should be fine. Regarding the OPT eligibility, you can read OPT for Second Masters