The scaling physics of quantum Hall transport in optimized topological insulators with a plateau precision of similar to 1/1000 e(2) /h is considered. Two exponential scaling regimes are observed in temperature-dependent transport dissipation, one of which accords with thermal-activation behavior with a gap of 2.8 meV (>20 K), the other being attributed to variable-range hopping (1-20 K). Magnetic-field-driven plateau-to-plateau transition gives scaling relations of (dR(xy)/dB)(max) alpha T-k and Delta B-1 alpha T-k with a consistent exponent of k similar to 0.2, which is half the universal value for a conventional two-dimensional electron gas. This is evidence of percolation assisted by quantum tunneling and reveals the dominance of electron-electron interaction of the topological surface states.