If you put a spell into a sequencer, then click it to remove it, then continue clicking on that empty slot, you will continue to get back per-day uses of the spell each time you click the empty slot. More Noticeable with a sorcerer than a mage, as it will restore per-day uses of the entire spell level for sorcerers.
Once you remove a spell from a sequencer slot, continuing to click on the now empty slot should not do anything until you select another spell for that slot.
Start new game with Adelia.
Console max XP/level.
Memorize 4x Sleep and 1x Minor Sequencer, rest.
Cast Sleep 3 times.
Cast Minor Sequencer, select Sleep.
Click the left sequencer slot 4 times, you will not have 4 sleep spells available.
Select Sleep again, twice.
Click on the left sequencer slot again twice.
Select Sleep once more. Click Done.
You have now restored all previous castings of Sleep, and have a sequencer with 2x Sleep spells at the cost of only one.