You can set the Injection-rate of the Fusion reactor to non-standard values.
I can set it to 3 or 100 (or probably some other weird values).
You should maybe apply the same checks you use when inputting via GUI (I'm no java expert, but I assume it should be possible).

Mekanism Version is 9.2.1
OpenComputers is 1.6.1.6 (shouldn't matter if I understood correctly how the interface between the mod is implemented)

Duplicate of #4030
Works as intended