Hi,
No, the calculations won't change. The patch I added only replace the indexes to be incremental for each order, instead of using the cart_product_id which increases for each product added by someone in his cart, in order to avoid reaching the maximum possible value for TaxCloud for the index. It doesn't touch anything else.
So regarding the specifics of whether a TIC should be taxable or not, I would first recommend to check with the TaxCloud support to see if the case you're in should indeed be taxed or not. Then, if there is really a problem with the plugin we can have a look at the specifics (address of the customer, TIC, settings of the plugin, etc) in order to identify the cause and see what can be done.