For the OP...I did a bit of legwork. Even the nicely set up Best Tracks differ in times by a good bit.
I looked at times by the same class at Mid America, NPWDRL, and the Nattys:
BASX Car: Fumbleitis, by HurriCrane, 2016:
Mid America, 1st place. 2.9177 avg time He was the winner with that time at Mid-AM.
NPWDRL, the next month, June 2016:
Fastest car was Cash Racing's Double Trouble, at 2.9624
DD4H Halloween race, 2016:
Fastest was TJ Racing's Wenly, at 2.9284
These are all pro times in the same year, on 3 different, but same brand/length tracks. Vastly different times.
Now I'm pretty sure that BASX cars didn't slow down .05 from Mid-AM to the next NPWDRL race one month later, and then speed back up .04 for the DD4H race just 4 months later.
That's just the difference in the tracks. The cars were likely about the same speed as before.
So when you want to know a good time....they're really not kidding when they say "It depends".