API Edge Settlement Correction Tollerance

[LNGRULES]

I need to bid out work to have two tanks jacked to get rid of some edge settlement issues. I have the report that gives me the allowable settlement but I don't want to use that as an allowable fix (I don't want to be re-doing this work next time the tanks come out of service for inspection). The settlement is due to erosion issues that we are also correcting. This is the first edge settlement issue I've bid out and I want to get the settlement taken care of but I don't want so make a spec. that is so tight that the contractors won't be able to reasonably achieve it. I know there's a lot involved with jacking, placing fill, then repeat until the desired level is reached but I'm not sure where to set my minimum deflection spec from the original tank design. I was originally thinking of using + or - .25in (allowable for said tanks ranges from 2.0 to 3.5). Does anyone have any experience or recommendations for this?

Thanks in Advance.

 

[IFRs]

If these are new tanks, see API 650 Section 7.5.5. If the tanks have been in service, see API 653 Annex B.