Thank you for your question and I understand your concern.
The burner switch/infinite switch differences are that they must match the burner. The left front and right front burners are rated at 2500 watts. The left rear and right rear burners are rated at 1200 watts. You will need to order the correct burner switch for the size of the burner it operates.
The right rear and left rear burners require burner switch part #3149404 and the left front and right front burners require burner switch part #3149400.
Do not substitute one for the other
or it could cause the switch to prematurely fail and it can cause the surface element to hot cycle properly.
You can look up and order
parts at Searspartdirect for Whirlpool range model RF262LXST1
I hope this is helpful. If I may be of further assistance as more details become available, please reply to this post.