But as you observe, it will be unequal. The reasons why far exceed this small space. Instead I'll note that IP SHAPING if you want to implement it can be done with a Linux based PC with a pair of ethernet cards and a week of your time configuring it to replace your router.

In theory the bandwidth is equally shared, but reality is that packet sizes, response times of the host machine that is serving up the content will tilt the results. Also, some firewalls on the PC/Mac add their baggage.

Best of luck,