If they don't want to mess with the door header - is it possible to skim off an inch or two at the thresholds & raise the light fixtures or replace with a shorter profile (height wise) light -second hand if you or they can find them to save the wallet. Used to sell rough terrain poultry units in East Texas area working with Bright Coop to the chicken growers & they did that all the time - of course, dirt is easier to move than - concrete & asphalt. My son is a commerical elctrician and many of his comany's customers are updating lights & the throw the old ones away,of course teh guys doing the job are alwasy looking for "a little side" money - check with some of the larger electrical contractors around your area.

Hey free advise is just that - maybe you can use it or maybe you will do a control-alt-delete - not an issue here.

The other idea but it is expensive Whe na I worked for Komatus - the provide 3.5" undercleance under the mast and times the lowered height would become an issue. Lift Tec 9supplier of all masts to Komatsu when hey were in Covington, GA)would builda "special" mast w/ 3" under clearance (the normal industry std.) to resolve lift height & lowered height issues - this was done by lowering teh tilt & axle mounts 1/2". But this had to be done on new production masts - no field modifications & Komatsu had to approve the changes to make certain other areas were not affect - like pinch points at mast cross ties, etc. (It is easy to spend other people money - eh?) but this free too!