Reduction in hours

[ROSSinHD]

Hi guys

My wife is reducing her hours from the week commencing 25/9 and going down from 37.5 a week to 32.5 a week. Mon, Wed and Fri is 7.5 hours paid and then Tue and Thur is 5 hours paid.

I have calculated her new annual salary £salary x (32.5/37.5) which is fine and confirmed. Her pay role guy is away until late october and as the reduction request has only just be granted by HR we cannot ask the payrole guy about Septembers pay and HR do not know as September run is being handled by another jurisdictions office. Not really an issue but my OCD is kicking in, in that my budgeting spreadsheet is currently wrong for September as I have spetember in at her new rate being the worst case scenario for budgets.

How do I calculate her September wage. She is paid monthly on the 25th which is her annual diveded by 12 but is stated as to the 25th in arrears and then to the end of the month in advance. Does that mean she is paid x days at old rate and x days at new rate or x weeks at old rate and x weeks at new rate for September.

Thanks

Edited by ROSSinHD on Monday 18th September 19:06