The rules are slightly more BAEC-friendly for standby paid-for upgrades on JAL domestic flights.

Standby upgrades are processed by customer category, with all OW Emeralds (from both JAL Mileage Bank and other FF programmes, including BAEC) being in the same category -- i.e. as a BAEC Gold you will get priority over all OW Sapphires (including JAL's own) and equal status with all other OW Emeralds (including JAL's own). Within each category, the standby upgrades are processed in the order that they were requested (i.e. check in time). My hit rate on upgrades to J on domestic JAL flights for 1,000 JPY (£7.31) as a BAEC Gold is very high. A great deal for the 40TPs.