Price Factor and Offset

[TecBrat]

I have only now become aware of price-factor and offset. I don't know if I have overlooked it for a year or two, or if it wasn't there in the previous versions. (not important enough for me to check at this instant)
What I want is to have an item priced by attribute, then have another attribute that has a price-factor of 1.1 and offset of 1 (10% upcharge).
My problem is that it is calculating the factor from the lowest priced attribute.
Is there a way of making it factor according to the selected attribute?
(I'm figuring it would probably need javascript in the tpl and a change to some function.)
Any ideas?

[Ajeh]

The Attributes Price Factor is computed off of the Product Price ...

In Priced by Attribute, there usually is no Product Price so the Attribute Price Factor has nothing to base itself off of ...

[TecBrat]

...In Priced by Attribute, there usually is no Product Price...

That's right, I set the item price to $0.00
(for a printing site)
I then have an attribute name "Print run quantity"
and attribute values "500","1000","2500" etc.
then I'd do something like set "500" to $99 and "1000" to $180...

Coating X is standard, but coating Y is 10% more.
I set coating Y to price factor 1.1 and it showed a price of 9.90.
So the function is aware of the $99 price. (I added it to cart, and was given a price of 108.90, so it works at least that well.) I just need to find a way of making it ... (Hold that thought, An idea just came to me. If it works I'll let everyone know.)

[TecBrat]

I just need to find a way of making it ... (Hold that thought, An idea just came to me. If it works I'll let everyone know.)

Okay, my idea put me in over my head, so I didn't make any changes. Perhaps my idea will make enough sense to a more experienced zenner who could help me out. It might help others as well.

find the code where "(+$9.90)", the computed additional cost due to the factor, is concatenated to the name of the attribute value in the dropdown menu.
change that to display the factor as a percent. ie 1= null, 1.1=+ 10%, 2=+100%(price would double)
when the item is added to the cart, and the price is figured, have the function that figures the factor-to-add check the attribute price prior to computation.

anyone care to help me on this? :-)

I am not asking someone to code it for me, but rather point me in the right direction. If it is the same function that causes it to display, I may need to copy it and call the copy(altered to show percent) for display and then call the original(altered to check attribute price) for add-to-cart.

I guess what I need then is the name of the function(s) and the filename(s) and approx line number(s) where it/they are called.

I think I know the answer to this (that would be "NO.") but can the functions_*.php be overridden?