The Government has confirmed that people who receive regular bonuses should be able to include them in their furlough pay, rather than just their contracted rates.
It could mean huge increases in the furlough pay checks of anyone affected - and might even be back dated to past ones in the future.
It comes after a battle between different interpretations of the furlough rules.
Martin Lewis didn't accept that supply teachers - who are contracted on minimum wage, then given bonuses based on their regular work - shouldn't get their normal amounts.
Umbrella companies disagreed - even publishing articles telling people not to believe "expert" advice that they could claim 80% of their full pay through furlough.
Now, Martin has been proved right, and the Government has even updated its official advice.
"We've been pushing on this a long time, I'd even got HMRC to give me a quote on it," Martin wrote on Twitter.
"And last week, finally the crucial Government guidance for employers was quietly updated to match that quote, saying: 'When variable payments are specified in a contract and those payments are always made, then those payments may become non-discretionary. If that is the case, they should be included when calculating 80% of your employees' wages.'
"This clears up the big issue for supply teachers in England and Wales. They tend to earn minimum wage, plus bonuses on top (to allow easy pay changes for different work).
"Many umbrella firms had told teachers they were just due 80% of minimum wage, as the bonuses are 'discretionary'. Now we hope all firms will furlough at the right amounts."
Of course, while excellent news for supply teachers, the change affects anyone who received regular bonuses on top of their wages.
Sadly, while it's good news for your next pay cheque, it can't be backdated to your last one at the moment.
"We've checked, and sadly furlough pay can't currently be backdated (though HMRC is working on changing it) but as firms are currently applying for the money for May's payrolls they are allowed to adjust the amount for that," Martin wrote.
