Alteryx not calculating the difference between two columns correctly

[jportello]

I have a simple workflow calculating the difference between two periods but the formula isn't working correctly. I have attached snip of workflow and excel of the output showing the inaccuracies. (some of the rows are being calculated correctly)

[jportello]

Its still not accepting it: 

[jportello]

Alteryx stil isnt accepting the formula..... tried both options below

[apathetichell]

tonumber - not tostring. totsring -> to string to number -> to number.

[jportello]

I dont understand what you are saying

[jportello]

You said in your original post to write to string and then later that "mult' is wrong which is needed to the round formula?