metro timing poblems

Apologies if this problem is already know...
I already worked with pluggo (version 3.5.2) building plugin with an hard use of internal timing to make process control
now I'm trying to change that plugin and I find that it don't work any more with the Pluggo last version (3.5.4).
To make some tests I try to build a simple plugin with metro and qmetro objects and it seem to have the same kind of problem:
with a metro time of 500 ms is evident that the metro object has timing problems in pluggo.
Some one has experience with this problem too?
Thank you for your help
Damiano

P.S. I do tests in mac an windows platform with max 3.5.7 and pluggo 3.5.4 with Protools 7 and Nuendo 3.