Following on from the post titled "How do I count the number of even weeks
in the current month."
I am taking the number of even weeks per month and assigning payments
against each even week in the month.

Since there are a maximum of three even weeks per month:
For the first even week I assign the maximum value I will receive for that
month.
If the middle of the month has not been reached I assign the remaining value
of £100
If it is none of the above (after the middle of the month) then I assign the
value of £0

I have the following
=IF(TRUNC(((A1-DATE(YEAR(A1),1,0))+6)/7)=A25,A28*100,IF(ROUND(B25-TRUNC(((A1-DATE(YEAR(A1),1,0))+6)/7)/2,-1)=1,100,0))

Broken down:
If the present week number (A1) = the start of month week number (A25)
Then multiply the number of even weeks in this month X £100

If the present week number (A1) divided by two = 1.5
Then the value is £100

Or else the Value is £0

Checking it the start of this month is week 4
The end is week 8

When I try changing my cell values this celldoes not update. I remain at "0"