Mailbox Sensor short battery life

I just had to replace the batteries in my Mailbox Sensor after ten weeks. (In each case with brand new Duracells.) I see that this time it says the (expiration 2030) batteries are at 27% Every ten weeks is inconvenient, particularly since there's no low-battery alert. Oh, and I wonder if I could've changed them without removing the mounting tape? I'm also wondering if the batteries showing this low brand new could be related to the Mailbox Sensor being 115' away, and being slightly obstructed, from the Bridge. (I doubt that, I would think that the battery strength reading occurs and the Mailbox Sensor, and reaches the Bridge accurately as long as there's a signal.)