The 17-20x is output token pricing: MiniMax M2.5 Standard at $1.20/M output vs Opus 4.6 at $25/M = ~21x. On input it's $0.30 vs $5.00 = ~17x. Blended (3:1 input:output) works out to roughly 19x.
Curious where you're getting 0.07 and 0.55 — are you looking at M2.5 Lightning pricing or a different provider?