The residential rows that matter first
Most households only need the domestic A-1 residential section. Start by deciding whether your account is protected or unprotected. Then find the slab row that matches the month's units. If you are using a normal household connection, you do not need to scan the commercial or industrial rows just to estimate a residential bill.
Why the fixed-charge columns are confusing
The public table mixes multiple fixed-charge columns with explanatory notes about sanctioned load, minimum monthly charges, and meter phase. Because that wording is not cleanly mapped to one consumer scenario, the calculator keeps those extra charges visible instead of pretending the table is clearer than it is.
What the calculator trusts most
The site trusts the published variable residential slab rates first, then shows GST and FC surcharge separately, and leaves the more volatile line items optional or manual. That approach is more defensible than copying one opaque total from an older calculator endpoint.