Do people in heaven live in time and space?
Your church would appear to believe purgatory to be subject to time and therefore space, since praying for the souls believed to be held in purgatory is encouraged, praying to shorten their time there (but not to affect their salvation), or so I've been informed here on FR.
So, if the concept of purgatory is subject to time and space, but God is not, does this pose any particular difficulty for the concept of purgatory, theologically?