Treat Wounds Critical Success

[Zanroth]

Maybe this has been discussed but I haven't found it in the message boards. For Treat wounds with an Expert in medicine you can attempt a DC 20 check to heal 2d8+10 on a critical success does it become 4d8+20?

[Deadmanwalking]

By the rules, it becomes 4d8+10, since the increase in DC/Proficiency is a flat bonus not subject to the Critical Success effect (which says it heals 4d8, not that it doubles the healing).