I approached the Battery Tender people recently about this same issue. They said it was A-O.K.
I use a Battery Tender Jr. on my Odyssey Gel for 3 years now with excellent results.
BSA 650 about 1969 Used, Denver, CO
Harley 350 (yes they made a 350) New, about 1971 Denver, CO
BMWs owned in sucession since 1975
R65 Used, Denver, CO
R90RT New, Denver, CO
R100R New Spokane, WA
K1100LT New Spokane, WA
2000 K1200LT Used, in 2001 then another
2000 K1200LTC Used, Canyon Red Metallic in 2003 then another
2000 K1200 LT Icon Used, Canyon Red Metallic in 2011 and still rolling.