there is no real advantage for an engineer to do it imo.
If you do a Bachelor of science on the other hand and you do advanced subjects throughtout ur degree, i think you end up with Bachelor of Science (Advanced), but that Im not 100% sure.
If you think ur a gun at maths then by all means go for it, and just change back to normal maths before the census date if its too hard.
better employment chances?? not really. first year marks are pretty useless anyway, just try not to fail anything.
and u can change into the advnced subjects whenever u want, even for 2nd semester maths...and in 2nd year u only do 1 more maths subjects....and the advanced version of that is REALLY hard.