Aragorn, I reckon you got it right.

Mauser 98 family types with a quick release ALL have the quick release at the bottom. Just think it through - if you release the top, the sling falls to the ground, where it gets muddy/trips you up. Release at the bottom leaves the sling hanging on the rifle, clear of the ground. And a bottom quick-release with fixed top loop makes sense for shooting, as you described. The US 1907 sling used on 1903s, Garands, M1917s, and often on Britishicon P14s and Mk4s as a replacement for the webbing sling, uses the same principle for shooting. See also Dana Jones/"Crown Jewels"/p.271/41B sniper.

Patrick