The buttons are bugged with the last version. I am able to speed-up the game with + and - keys but when I click on the icons in game it set its self to 0.50

Unable to replicate, sorry.
(Please note as well that this is a personal edit of an existing mod that changed about ten characters in the modfile, uploaded to the portal in the hopes that others find it useful. If you're able to identify the cause and/or provide a patch, I'm happy to update the mod, but I don't currently have time to troubleshoot this or other issues on any of my mods beyond basic attempts to recreate the issue.)

I don't see how TrainAdmirer could not replicate the problem. As I type, I am staring at a fresh base game with only base and Speed Control Scaled enabled and the buttons are bugged. By that, I mean if I push one of the slow buttons then the speed will go to x.5 and after that none of them work at all, neither slow nor fast. But I can respect real life taking a priority over his time. I do not have the mod experience to fix such things.

The hotkeys of Shift + and - work. I don't know about the others as I don't use them. Note that the + and - are the keys next to Backspace and not the ones in the Numpad.