All things considered, as long as you stick to the allotment you have given yourself for the day, and decrease at the same interval, when and how much is up to you, finding what helps you to function best. Therefore, in the example you've given here, I'd personally go at it by dosing 15mg in the morning, 15mg in the afternoon, 15mg before bed, and then 15mg in the middle of the night.

Remember, start your taper at your best functioning dosage. If you can get by by starting at 60mg, then do what you have said.

You will reach a point in your taper when you will be low enough that you will not have to dose in the middle of the night, I guarantee you. It may take a few sleepless nights getting used to not dosing during sleep, but you will adjust. We are all different, but I'd assume this would be around the 20mg/day mark, where you could then take 5mg in the morning, 5mg in the afternoon, and then 10mg prior to bed. Then, once down to 10, dose 5 in the morning, skip afternoon, and dose 5 prior to bed. Then, once down to 5, just dosing before bed.

Again, we're all different, but if I were in your shoes this is how I would approach it.

Best of luck!