Amazon - can you explain me that ?

I have plenty of days where i have sales but no commission

when i check certain days it gives me a commission but it seems not to be added.
the yellow line are the orders ..... the green the commission.

do they add it a few days later ?

It's easy to understand, assuming you're an affiliate.. your commissions are earned whenever a product is shipped to the customer.
So you can have 10 sales in a day but the comissions for these 10 products appear only when the seller ships to the customer... it can be the same day, next day or never...

Commissions are only earned when a item is shipped. I had days where commissions where added after a week. Regardless of the orders if the items is not shipped you won't get the commission. And if a item is returned the commission that you've earned will be deducted from your main account.

makes sense ... thanks