DTC P0420 & P0430

While driving on the highway the other day the "check Engine Light" came on. I scanned for the codes and got P0420 & P0430 which indicates a catalytic converter efficiency issue. I reset the ECM and the light has not come back on yet although I expect it to come back on. I checked the toyota web site and found a TSB that states the fix for this problem is to flash the ECM. I went to the dealship on Saturday since it is time for the 45,000 mile checkup and explained to them what I found and told them that I reset the ECM. I brought along a copy of the TSB which explains that the ECM must be flashed to correct the problem. The RAV4 runs great and there is no noticeable difference before or after the ECM reset. Has anyone else experienced this yet? If so, how has the problem been resolved? Thank you.