Hi,

I would like to produce a % return value based on the start and end dates for a task.

For example.

My task productivity is based on what time of year it is,
between 2 March - 31 May productivity = 90%
between 1 June - 30 Sep productivity = 100%
between 1 Oct - 30 Nov productivity = 90%
between 1 Dec - 1 March productivity = 80%

if task A starts 10 July and ends 30 Aug the productivity would be 100%
If task B starts 1 Sep and Ends 1 Nov then productivity would be averaged (approx 95%)

So I would like to create a formula which would return this % and in turn slightly change the end date of a task (it is a bit of a loop so not sure if that would work)

Hope that is clear

Thanks

JS