Hi,
In the settings of your menu item, under the "products options" tab, you have a price display method setting in order to configure which type of display should be used. It seems that you selected "all", in which case all the prices of the variants will be displayed.
If the prices are loaded from the variants, there is no particular order.
However, you can setup the prices you want in the main product and in that case, the prices from the variants will be ignored and the prices of the main product will be displayed based on the order you have them in.