25mm standoff using shims instead of grout

We are looking at a detail that was originally designed with no standoff. Now a 25mm standoff is required and the contractor is asking if they can build this out with steel shims. We have altered the Hilit Profis calc to include a 25mm standoff with grout (attached) and the bolts are still working fine, but there's no option to model shims instead. Would steel shims instead of grout alter the bolt calcs? Is there anything else to consider with shims as a replacement for a grouted solution?