Since first lockdown in my country, when dishwasher tabs went missing in stores, I got used to use 1/2 a tab for each wash. Turns out dishes were just as clean as with a full tab. To this day I keep using 1/2 tab per wash.
To push your example even further, I once forgot to load anything and Imagine my surprise when I opened the dishwasher and everything was really clean, maybe except one plate.
