Q. Does it even matter if TT just treats them all as long term cap gains and then makes the rate calculation based on the rest of the reported cap gains?
A. No.
TT uses the IRS "Qualified Dividends & Capital Gains" worksheet* to calculate the tax on Long term capital gains, capital gains distributions and Qualified dividends. On that worksheet, the qualified income will be totaled and the total allocated to the 0%, 15% or 20% rates, as needed.
*In some cases a "Schedule D worksheet" will be used instead.
