In case of multi restaurants, this still makes a ''real life' problem. Right now the addon prices can be added only once and for a single restaurant, since the prices of same addon items vary for other restaurants.
For example the price of a Pizza- Large is 600 for restaurant R1 and 650 for restaurant R2, If we add ''Large' as an addon, we will be able to assign the prices as value of R1.Large= 600 and R2.Large= 650
This way it could be able to fix different rates for items with same addon name coming from different restaurants,
If there is any other existing solution for this then please let us know!