Up-sell a sealant on top of your AIO.
I have 3 levels I offer...
Exterior detail: wash, clay, AIO. Up sell sealant.
Stage I: wash, clay, polish, sealant.
Stage II: wash, clay, compound, polish, sealant.
And then I also offer coatings for the paint correction details (Gloss-Coat, Opti-Coat Pro...