250ms is for key presses and mouse buttons. any keyboard program or mouse clicking program that lets you just hold down the assigned button, and it casts the macro, can be set for how fast it pushes the said button. So far as i know you cant set mouse scrolling to 250ms, because you are manually scrolling all the time to get the desired effect.
programs: any gaming mouse and keyboard has program to set ms speed. internal program would be Autohotkey (AHK). i hope i answered your question.