Question

During the grace period, if you have multiple copies of Studio One Professional or Studio One Artist in your account, all copies are stamped as upgraded.  However, you only get one copy of Studio One 5 or the  PreSonus Sphere per account, not per product.  This is only a rule for those registrations that occurred during the grace period. 

does this mean only one of my activations will be upgraded?

Answer 1

No, it means that if you purchased multiple licenses (Of which each license has 5 activations), only one of those licenses would be moved to SO5/Sphere as part of their grace period.

If you have one license and have activated that license on multiple machines, all the machines will can be moved to SO5 once you upgrade.

It's only if you've purchased multiple copies of SO4 within the grace period that this clause applies.