MarketPress product prices don't update when switching variation combos

I am working with MarketPress and just created a new product. My products have only two variations (size and color). There are about 20 different size options but only 4 different colors but only the sizes determine the price ( e.g. large blue and large red are same price). I do not have a base price for the product because it depends strictly on the size the customer desires. The color variation is purely for shipping the correct product.

The problem:

When viewing the product from the front-end, I select the size variation I want and the correct price is displayed (a default color is displayed). When I change the color to the color I really want, the price defaults to the base product price (independent of variation). [Side note: when I created the product, I set the base price to $1 because this field could not remain empty and my prices are dependent on the size that is selected so my product has no base price.]

Now with the price set to $1, if I switch the color variation a second time, the loading pinwheel spins and never updates the price. Ultimately I have to reload the page.

Again, if I switch the color option to a different color for a particular size, the price resets back to $1 despite the size variation price being set to $25 (all colors for this size should be displayed at $25). Even though the product display incorrectly shows $1, if I add the product to my cart, the cart correctly displays the price of the item.

I am concerned that if the price is not properly updated when my customers switch variation combinations then my customers will become frustrated and go elsewhere. Any ideas?

Already updated theme, switched theme to 2012, updated MarketPress and deleted product/created new product.