I wouldn't know what an alpha blended sprite was if it bit me on the bum.
However I do know that from a 'technical' point of view the usual reasons why a piece of code cannot be used elsewhere in an otherwise similar system are
a) it has been incompetently implemented
b) it has been deliberately implemented in an incompatible way (for instance to try to get more business for your company)
c) it has been implemented with no thought to similar target platforms.
d) it was the only solution available at the time given resource and funding limits.
e) your client has insisted it is done in a particular way for their own curious reasons.
f) it is in fact very simple to re-use it on the similar system but for political reasons you don't want people to know this.