Delta virus def update around around 50 MB

Hello,

For one of our customers we are in process of upgrade from SEP 11 to SEP 12. However we noticed that these machines which are still on SEP 11 are downloading very big delta updates. See screenshots. Is this normal? As far as I know the delta size usually is very small, less than 1 MB.

Also another thing that I noticed is that in some of the revision folders there is Full.tmp file (and here is where we see such big deltas), whereas on the other screenshot deltas are much smaller.

And one more thing, because of disk space limitation, we keep 16 revisions.

Regards