Am I calculating battery life expectancy correctly for this RF receiver?

I have this RF remote/receiver. Though the manual says battery life for the receiver is at least 12 months, I easily get 2 years of operation on a fresh set of batteries. The receiver 4 uses AAA batteries, so that should be 6V at 1200 mAh. Assuming there are external factors like self-discharging, the battery life is further decreased by 15%. I’m basing my calculations from this calculator.

Battery Life in years = Battery Capacity in mAh / Current in mAh / 24 / 365 * (1 -.85)

So based upon a 2 year life span (and assuming the .15 constant is correct) is it fair assume that the receiver is drawing on average around 58uA?

I realize I’m making some assumptions here, like the .15 constant. And I’m fairly sure the receiver is operating in sleep mode and waking up, but I want to make sure I understand this before addressing those assumptions.