Driving stepper motors

[h-g-t]

I am looking at the 36v stepper motors removed from an old Epson printers. The both appear to be uni-polar and the circuit diagrams shown in the manual are the same. I am hoping to re-use these employing a miniboard and bits salvaged from the main circuit board.

However, Epson have chosen to drive the 48-pole carriage motor through a switch IC, whereas the 200-pole paper feed motor uses a transistor H-bridge.

Is there any reason why two different methods should be used for driving similar motors? I am hoping I can use the same IC for both.