Different calculation for mid-month changes

It would be good if there was a different calculation for mid month salary changes - we have had 2 people who got a salary increase on the 4th March but due to the way the system calculates on working days in the month and March being a short month they have actually ended up with less monthly salary than they would have gotten if they had remained on their old salary

Is it possible to have the option to do new salary minus old salary divided by 260 and the difference for number of working days?