interfering with selection shipping rates

It seems the Dynamic Pricing plugin is interfering with the selection of shipping rates in the cart. When I deactivate the plugin, I don’t have any issues. When I activate it again, after selecting the shipping rate and a grey-out of the rates, the products in the cart grey out and the selected shipping rate doesn’t stick. It goes back to the default selection. Initially things were working OK as far as we know.
My client is using the Dynamic Pricing plugin extensively so maybe he made a mistake in one of the many rules he entered? Or is the free version only capable of handling a few rules and should we switch to the paid version?
I can provide you with the login information for the dashboard. At the moment, the Dynamic pricing plugin is turned off, so things are working fine in the link I provided above. I would like you to be able to turn the plugin back on, to see the selections don’t stick then. I also would like you to have a look at the rules that have been entered, to see if the problem originates there.
Thanks so much in advance for your help!!

The page I need help with: [log in to see the link]