Populate a future date field based on date equation using last date

I am trying to create a pretty basic date equation field but am not having any luck. My record has a last service date. It also has a number field dictating the number of times per year the service should occur.
I am trying to create a next service date based on the last service date and frequency per year field.

My equation:
{Last Service Date}+(365/{Frequency per year})

My input is a date.
My output is a date.
I am doing it in terms of days.

My output keeps coming out as the Last Service Date as if it has ignored the equation.

Please help. Thanks

I found the same, so I tried using an intermediate field to calculate the service interval, and then used that as the number to add to the last Service to get the next service.

Last Service = date of last service
Frequency is how many time a year the thing needs to be serviced
Service Interval is simply 365/{Frequency}
Next Service = {Last Service} + {Service Interval}

Adds an extra field but who cares - it seems to work.

You have the solution alright, but your screenshot shows the next service date only 4 days later. You may have forgotten to update a record in the row to force an update in the calc.

Actually the dates are mm/dd/yyyy in screenshot. It’s 4 months later. I figured most readers are from US. My comment it was dd/mm was wrong so I’ve removed it.