We talked with our FS about blasts before our last cycle (we decided to go with 2, 3 day embies instead). He said that they would have thaw'd all 7 of our embies and put one blast back and then re-freeze any others that got to blast.

I feel the similar about thawing everything to get a blast, I have a fear that none of them will get there and we will lose them all.

Saying all this we have decided to do this next time if the most confusing cycle I have ever been through ends!!