[Dragokas]

Thank you for the feedback!

It's a completed plugin. I don't want to complicate it with such things.
Why you may need to change speed in steps?
Usually admins:
1) hold 1 specific speed they required for their gameplay balance.
2) or use perks system where upgrades available as awards for some events.

In first case, change speed required in server's scripts for each weapon or use Silver's Mission and weapons editor.
In second case, you may want much more complicated plugin something like perks from Marcus101RR or KrX.