Have the guy set the IP at 140 with a near-empty tank. Then check it with a full tank, the tech will be surprised to see the IP is 130. The MK17 is balanced but not completely, so like unbalanced diaphragm regs the IP rises as tank pressure decreases. Anyhow, it's no problem because the atomic 2nd is balanced and will compensate for a 10PSI IP swing without you even noticing. But if the tech sets the MK17 at 140 with a full tank, you'll be up over 150 with a near-empty and that's probably not ideal.
Personally I keep my IP fairly low, around 125 for the MK5/10. I find high performance balanced 2nds do very well at a lower IP and it may be a bit easier to tune them. But that's an opinion, not a fact, and I have zero experience with the atomic 2nd stages. One nice thing about low IP is that IP is a bit like blood pressure in that it typically goes up with age, so my MK5s can go several years before I need to rebuild them.
Just remember to tell the tech to set the IP with a near empty tank if he's going to set it at 140.
