v1.51 one-time charge added multiple times

[moesoap]

Hello.

In my product info page customers can order more than one size and one colour and add these products to cart. As my website is an embroidery business I am required to add a setup charge should the customer wish to have their logo digitised, which I am able to do using attributes. My problem is that when the customer selects, for example, Size - 10, 12, & 14 in Colours - Blue, White & Black and chooses one time setup charge, within the cart the customer is charged 3 times for setup. I have added screenshots to demonstrate the problem.



From what I can gather there are 3 possible solutions...

1. Add Setup Charge as a Product and direct customers to add this to cart separately
2. Allow customers to select Logo Digitising in the Shopping Cart and price could then be added to cart
3. When customer clicks add to cart, redirect to custom page where customer selects personalisation options, then redirects to cart.

As I am not great with php options 2 and 3 would be beyond my capabilities. And as for option 1, it is a difficult task to ensure customers understand and follow that procedure.

Is there an option I am missing here? Or can anyone suggest a way to implement Options 2 or 3, from previous posts in the forum? Or am I looking at this completely wrong?