They used to use the same FET for all outputs with 1.0. Should be no problems doing that.
I think apart from cost, he changed it so he could fit 2 small FETs in place of a larger single FET, and add a third FAN output.
1.0 had 5 FETS (2 extruder, 1 HB, 2 FAN), whereas 1.1+ had 6. (2 extruder, 1HB, 3 FAN). The smaller FETs are quite suitable for driving something as low power as a fan.
I think apart from cost, he changed it so he could fit 2 small FETs in place of a larger single FET, and add a third FAN output.
1.0 had 5 FETS (2 extruder, 1 HB, 2 FAN), whereas 1.1+ had 6. (2 extruder, 1HB, 3 FAN). The smaller FETs are quite suitable for driving something as low power as a fan.