Looking at their pricing page for China, K3.1 seems to be about 30% cheaper than K3.

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Model K3.1 Pro K3.1 Pro Highspeed. K3

Input ¥13.00 ¥26.00 ¥20.00

Output ¥68.00 ¥136.00 ¥100.00

Cache hit ¥1.30 ¥1.30 ¥2.00

Cache write ¥13.00 ¥26.00 ¥20.00