03 Road King Rear Axle Nut Tourque Spec ???

I found my drive belt loose, found that the rear axle had slipped forward just abit. Tightened belt and went to re torque rear axle nut, looked in the owners manual and it said tighten to I think it was 15 to 20 ft lbs. That spec doesn't seem tight enough to me, in fact I know so because it already came loose once. I see other posts saying people are tightening their rear axle nuts to 50/60 ft lbs which seems a bit more reasonable. Is my manual wrong ???
Like I said I think mine says to tighten it to 15 to 20 ft lbs ... Thanks !!!
Bike is a 03 Rd King...