My understanding is that this depensation is available to this generation only. The Church does not want to have men skirting the discipline of the Church by becoming Epsc. and then changing to RC. Do you have some evidence for that? When I read the dispensation, I don't recall a time limit.
It would have been in an orthodox Catholic journal. I'll try to find it but not today. We have a priest friend spending the night and I have to get the guest room ready.