A later release date doesn't mean more development time ... the working hours per milestone surely will not change (that would require additional money and pushing back the release date already produces cost since the studio might not be able to reassign their workforce under the terms of the currenr contract with EA)
It kinda does, though. A postponed release date means that there's potentially less reasons for crunching, which means that developer productivity goes up. It can also mean more time for QA, leading to a more polished product.
What I was saying is that manhours might not become more just because the deadline was moved; If the budget only goes for, say for arguments sake, 1,000 manhours per employee, it doesn't matter if these 1,000 hours are 3 months or 6 months.
Of course it does impact the quality of the work because there is less time pressue, but it doesn't allow for more time consuming tasks unless there is more money going to the project that would cover the additional hours the staff puts into those.
All of this of course is void if EA would be allocating more money to the studio besides covering the additional months of operating cost for the staff specific to the project.