First, I'll just second Luke-Jr's reply above.
In any case, if you're to lower the default auto-payout amount from 100 TBC to 40 TBC, then by the same logic, maybe you should reduce the minimum payout amount from 10 TBC to 4 TBC?
About this, the 10 TBC minimum is for coinbase payouts. Because some miners do not function properly with large coinbase transactions (with hundreds of outputs) it was decided to put an absolute minimum on coinbase payouts of 10 TBC. Due to another unrelated issue with a particularly annoying botnet, an absolute will-never-pay-out-ever minimum was set at 2 TBC. Those that fall between 2 and 10 TBC just wont get generated payouts and I instead pay them manually periodically. The 10 TBC lower bound for the custom minimum is so that people can still automatically enter the payout queue with their custom minimums.
Technically balances that timeout that are under 2 TBC get donated to the pool, as per rules setup a while back..... however, like the % donations in the control panel, I haven't actually coded that yet due to finite coding time being better spent on other improvements.
-wk