Mike, I don't see any times listed for the Amsat tracking. I think the problem is people are saying that HRD "lags" (ie, the track is correct, but several seconds/minutes behind). Regardless of if that is true or not, what I would suggest to verify HRD's tracking is to open two windows, one with AO-91 or 92 in HRD (realtime, during an actual pass), and one with Amsat Argentina's website:
Be sure to enter your correct grid square and select the correct satellite, and it will tell you current Az/El and doppler frequencies for Uplink and Downlink. I've found this site to be very reliable, and no installs are required (it runs in the browser).
Regarding the control of two VFOs simultaneously... we're working on this next. On another note, I've been comparing satellite passes between HRD Satellite Tracking and AMSAT's tracking and I am unable to find any differences. Here's an example with AO-91: http://www.hamradiodeluxe.com/AO-91-Pass-min.png