First off, I'd like to apologize if this is a stupid question. I am new to working on my bike outside of derailleur and brake adjustments, and have not been able to find my answer by searching.

My situation is that I have a 2000 Trek 6000 that needs a new drivetrain. I have installed a 73mm shimano un54 square taper bottom bracket with 113mm spindle length.

I have two cranks:
Shimano 7/8 Speed Alivio Mountain Bicycle Crankset - Square Taper - FC-M410
Which is giving me a chainline of 55mm
AND
Shimano FC-M361 Acera Crankset (Black, 175-mm 42/32/22T 7/8 Speed)
Which is giving me a chainline of 50mm

I wanted to use the alivio, and my understanding is that it should give me a 47.5 or 50mm chainline with a 113mm spindle length square taper bb. However, that is obviously not what I am seeing. Is this an issue with the particular style of bottom bracket that I chose? Should I have chosen something else? Is this crank not for a typical square taper BB or something?

Any help would be appreciated.