Yes, you could change the scale. But the processing power ratio stays the same. At the price per 1k you listed, it's still cost-effective to crack this captcha at 1 per 10s automatically. But noone will accept waiting 100s to post anything.
If you start calculating the hash in the background, that could be useful. I might not want to wait 100 seconds after I've finished my reply, but I don't imagine I'd mind waiting 100 seconds from the time I first opened the thread or started typing.
