Using PSM in PVSyst

Forums: 

I'm struggling with getting consistent, reliable results when trying to use the PSM datasets, both v2 and v3, in PVSyst. I've been contributing to the PVSyst thread here:

https://forum.pvsyst.com/viewtopic.php?f=22&t=2480&p=9512#p9512

Can anyone at NSRDB help understand why I may be seeing such variability in time definition & global horizontal irradiance? Thanks!

By the way, it would be great if this forum had a search function.