-apparently you need more depth, which means longer screws...
-it's common for pickup cavity routing to be deeper under the 'dogears' where the screws reside-
-This could be as simple as removing a little wood down there, but if you're uneasy about it, consult your local axegrinder...
check , & check again before drilling out the back of yer axe by mistake!-
If it's an old warhorse, don't worry too much about rough edges and doing it yourself...
-If something collectible/valuable, then preserve it's integrity by spending some jing-a-ling that it can bear close scrutiny...
Cheers from Drac...