Costs
The cash you still pay on an award
Carrier surcharges and departure taxes are the reason a free seat costs ₹20,000. Which programmes charge them, and which do not.
Two different charges, often confused
A departure tax is levied by the country and the airport. Everybody pays it, on every ticket, and no programme can waive it. A carrier surcharge is invented by the airline, and whether you pay it depends entirely on which programme you book through.
The same seat, two prices
This is the whole reason the board shows cash beside every fare. A business seat to London can cost fewer points through one programme and several thousand rupees more in surcharge, so the cheaper chart is the more expensive ticket. A fare without its cash is not a price.
Where a programme's surcharge is published, the figure here comes from that page. Where it is not, no number is shown rather than a guess.
What to check before you transfer
Price the route on the board, read the cash line, and only then decide which programme to move points into. The difference is routinely larger than the difference in miles.