I suggest to write this…
I see no reason why not to change it… I would say it is a good call! 
I also found something about quaternion multiplication:
When you say it would save time you mean you have already tested it? Because my experience with that is that it really depends a lot on the machine (Intel vs AMD vs PPC) because of the (floating-point) functional units they might have, additions and multiplications might not differ substantially.
I removed that performance statement, but you were faster…
Of course, these microbenchmarks are just quick hacks.
[edit]Seems like I got fooled, and my version is actually even a bit slower than the original one, but I still need to test a working version. At least I learned something about microbenchmarks 
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