Well, and at that price range difference, its pretty obvious they used a cheaper fluid then real ATF+4, which is fully synthetic and often more expensive then a Dex/Merc base fluid.
Since your receipt says MaxLife, and MaxLife meets:
Performance Levels/ Approvals GM Dexron IID, IIE, III, VI; Ford Mercon, Mercon V; Allison C-4, TransSynd*, TES-295; BMW LT 71141, LA 2634, MAN 339 type Z1, Z2, V1, V2, Mazda*, Mini Cooper* CVT EXL 799, Toyota T, T-11, T-IV; Chrysler* ATF+3; Mitsubishi* Diamond SP-II, SP-III; Honda ATF-Z1, MB Approval 236.1,2,3,5,6,7, 8,9,10,11, Nissan* D, J, K,-matic, Volvo 1161521, 1161540; Audi* G-052-0250-A2, GM9986195, ZF-TE-ML-14B, 16L, 17C, JWS 3309, Voith* G 607, 1363; KIA* SP-II, SP-III; Suzuki*, VW TL 52162
None of which are ATF+4, you have a legitimate [censored], because your mechanic installed a non satisfactory fluid.
I'd get them to change it. Guarantee they tell you its no big deal though.