I fail to see how anyone who has a full round can adhere to the same day, time after time. You lose two days through extreme weather, you are now two days behind. Unless you have short days or you work weekends how can you fit two extra days work into your schedule to bring you back to the original day?
We treat a round as literally that: a huge circle. Start at the beginning, work all the way round till you get back to the beginning and start again. Some months we may be a little ahead, because there are fewer 8-weeklies, but that balances out on the next cycle when there are more 8-weeklies.
Don't lose sleep over slavishly trying to stick to 'schedules' - your customers will never notice and if you have a full round you should never be early.
Set yourself a daily target - work till you achieve that target and stop. This could include a few extras to help make up for a poor day previously. Provided you are earning what you want to does a day here or there matter?
Being self employed means you decide when you work and when you have a day off. If you drive yourself to always be exactly on time, and worry if you're not, you might as well be employed, and let someone else do the worrying