The O/P ask about replacing an auxiliary shutter in an H4D .
There are no shutters in the true meaning of the word in any H bodies.
This repair has nothing to do with A/F and there is nothing to calibrate.
Well I'm sorry but Hasselblad disagree with you:
Auxiliary shutter replacement (factory service only) Euro 325.00**Note: This price includes an AF calibration. May appear as 2 separate lines on the invoice, but the sum will be as listed.This is under Body repairs nothing to do with the lens shutter, and I have no idea why AF needs recalibration. A main board replacement also requires this but
Auxiliary shutter drive unit replacement 395.00 does not. I don't know which repair is needed obviously.
I am not dishing Happyblad at all, I was careful to say that clearly I have no reason to do so just as I have no reason to promote factory service, I am pointing out to the OP the options available and my opinion, worthless though it may be, on those.
My H1 factory service visit was under 10 days door to door last year I do think 4 to 6 weeks is unreasonable as is the rental charge, BTW are Happyblad still in business? The web site is unreachable and their last Facebook entry was over 12 months ago.