Generally, the expectation is 24-48 hours, depending on the extent of additional analysis required.
Just so you know, lenders also ask for revisions, CG. In fact, many of the revision requests that come from AMC's originate on the lender side. In my own company, we send out several revision requests a day. Not all are related to value reconsiderations, but some are. The ones that aren't are usually a result of shoddy appraisal reporting. In the case of the value reconsiderations, to me that is just part of the job. Ours is a profession of opinions, not facts. And, since opinions can be questioned/challenged (unlike facts), it becomes part of our world. AND in many of the cases where value reconsiderations are proffered, I personally believe the appraiser to have been too conservative in his/her conclusion (not that that matters). All that to say that - yes, I understand what a PITA revision requests and ROV's are, but they're also a PITA on the lender/AMC side... I have no control over how long it takes an appraiser to re-submit a 'corrected' report (talking about revisions now). We've had situations where we've waited 2 weeks for an appraiser to spell a borrower's name correctly. That is just disgraceful. I could go on, but you get the point.I know you know that I think AMCs are terrible for appraisers and here is another reason why. The AMC model is known for requesting revision requests that might include considering additional comps. There are AMCs that want revision requests in FOUR hours; what idiot thought that was a good idea? I think most want then in 24 hours. If I have a full day scheduled the next day I might not get to it that soon but most can be taken care of in that time.
When the AMC wants additional comps considered we cannot (as you know) just throw a comp in and turn the report back in a few hours. We must, as you know, verify, research and then drive the comp and photograph it. If the appraiser is busy and schedules based on geography they might have to screw up their entire schedule by have to drive 30 miles both ways to take a comp photo of an extra comp.
That extra comp in Tecumseh, MI might take four hours of my time to put in the report and if I already have Tuesday full it might not happen until Thursday or Friday. The AMCs only want things fast and cutting corners is fine with them as long as the revision is done ASAP without regard to quality or other commitments the appraiser might have.