The Energon Pub

It seems to me that #1 and #2 sell for more than #7 and #8.
It seems as though #1 sells higher than #2, #7 more than #8.
I based my observations on ebay, is there a REAL REASON behind this? Or are they all worth the same in reality?

Thanks in advance,
Ed

BT-01 #7 and #8 were simply variations of the first release, and #1 and #2 are second releases, slightly remolded, and include an attachable shoulder cannon, which is quite nice.

The cannon makes #1 and #2 the more desirable BTs, there fore more expensive.