66B BE??? lol there is no such thing. I'm going to assume with Jon as well, & think you meant 66K BE instead. However, I'd really recommend not using 66K BE at all after using 22B BE. Why I'm saying this is because after using a lot of moves for your combo, your damage to further attack will be greatly reduced. Trading extra meter for a very small amount of additional damage is not worth the meter. You'll be ripping yourself off for something you could have used it for in a better way. I'd recommend just using another attack you could be doing to make little difference then trading more meter. Almost no 2nd BE is good enough to use for more damage unless you are certain it's going to either A: Kill them or B: grant you more then just 8-10+ plus damage.
This is something I always keep in mind when training. Use your meter wisely for the greater good.