I think there’s potential for abuse with the new rules;

Set your employees base rate to be 7 hours a day, four days a week down from the usual 8x5

Make the 5th day and the 8th hour extra or bonus work.  Reduce wages but add bonuses to make up for the shortfall 

You now pay much less on their holiday rate.

If you’re already on a low rate but get weekly bonuses that you rely on to pay the bills, you’re going to be in for a shock when you go on holiday.