"Every 100 milliseconds - Add 1 to Value"
"If value is 50 - Do this"
"If value is 100 - Do this"
"If value is 150 - Do this"
So you would want to change this to -
Always - add 50 * Timedelta to value
"If value is 50 - Do this" Will take 1 second
"If value is 100 - Do this" Will take 2 seconds
"If value is 150 - Do this" Will take 3 seconds
If you halved that value (50 to 25) then the steps would take twice as long. Also note that timedelta uses decimal places, so it will be hard for it to land precisely on "50". So if you modify those variables to greater than/less than etc.
It seems rediculous at first, but it does get very comfortable quite quickly. Have a look through the second topic Tulamide linked to, it is one where he helped me come to terms with Timedelta.