Limits on 'service fees' charged by taxi payments processors have had their expected impact on the profits of Cabcharge, with revenue from this source down by A$11.1 million, or 35 per cent, to $32.9 million over the half year to December 2015, compared with one year earlier.In Western Australia and New South Wales these fees are now capped at five per cent, catching up with a limit already introduced in Victoria. This cap is half the level of the fee once charged by taxi operators in those states making use of the fare payment system operated by Cabcharge.The firm made some offsetting savings and profit gains, with the group result down $68 million, or 22 per cent, to $22.4 million.Affiliated taxi operators must be making more use of rival payment processing systems, with fares processed by Cabcharge up only $2 million, or 0.3 per cent, to $538 million.