Would you measure the length and width of a framed piece (the actual frame size versus the art work size) to come up with your linear pricing?
Love your work. Great website.
There are a few parts to this question I want to talk about. First, to answer your question simply, when coming up with my linear pricing,  I only charge for the price of the artwork itself. There is so much more to consider though when pricing.
This is your product. You get to decide how you base your prices. There is no single right way to price an item that is one of a kind. I mean there are general guides I recommend (like not lowering your prices or having discount sales), but it’s your art. If you choose to include a frame on your work, it’s totally acceptable to charge more to cover the cost of that frame.
Some artists will only sell work that is framed, so their prices generally reflect that.
I’m a bit different than many artists when it comes to this. If I’m displaying a painting at a gallery or show, it will  be framed unless it’s painted on a box canvas that isn’t supposed to be framed. The price of that painting or drawing is generally going to be the same as what the artwork is listed for on my site unframed. I just sold a painting to a local city for their permanent collection where the price of the painting included the frame. It was my usual price for a 24×36″ oil painting, so the frame was just a sort of added bonus for them. It’s just easier for me to include it all together than get into the whole “well it’s this price without the frame or this much if you want the frame”. The frame cost me around $50. On a $1200 sale, I am comfortable eating that $50 frame cost.
If I were to frame a piece in a much more expensive frame I would likely increase the price of the overall piece. You have to remember, you’re not a kia dealer competing with a kia dealer down the street. You don’t have to do everything exactly like another artist does. What you create is one of a kind, and that gives you a lot of freedom in deciding how to base your prices.
There are some things that are just good practice when coming up with prices but nothing is set in stone. You get to do whatever works best for you and your business!