The tax is deductible regardless of where it is reported.

Example:

Purchase a fuel filter..............cost is 15.00 for the filter........sales tax is .75........total cost 15.75.

When record it in the books................ put 15.75 in the supplies expenses............

OR.............put 15.00 in supplies, and put .75 in the sales tax paid expense account.

The cost of the filter, and the related sales tax, are both deductible.

Two reasons for including the total invoice price of 15.75 in supplies expense.........

1.  It is faster.........do not have to enter two numbers.

2.  My personal view-------- "taxes" is an account/line item in the tax return which needs to be "clean", and detailed, in order to allow any reader of the return to match up the components with other larger items in the return.......such as property taxes and related interest expense, such as on a mortgage on land purchase.

Another consideration...............if the sales tax is paid on capital purchase, such as on an endloader when the state deems that endloader to NOT be directly involved in production...............and I have not researched this for many years.............but I think the sales tax is deemed to be a cost of acquisition (just like freight----although few follow that rule), and therefore has to be depreciated along with the base cost of the machine, ie cannot expense the sales tax in the year of acquisition, and depreciate the machine over 7 years.

I would bet that you would find it to be more efficient to merely record the total invoice, including sales tax, and not take the time to allocate it among the expense groups that might be on that invoice.