German agents should not sign up for Lufthansa's Preferred Fare Programme, a leading consultant said.
Andreas Wilbers of Wilbers Consulting said it would be counterproductive for the airline to push the scheme through and if agents refused to sign up for it, it would be "swept away."
He was speaking at a seminar on efficient travel management at Business Travel Days at the ITB in Berlin.
Mr Wilbers said the scheme, announced in January by Lufthansa and its fully-owned sister airline SWISS, was all to do with the airlines' negotiations with the GDSs with the German carrier aiming to cut €2.5m from its distribution costs.
Under the proposals, one way fares on Lufthansa and SWISS will go up by €15 one way and €30 for a round trip on tickets bought in Germany and Austria from July 1.
Prices for tickets bought in Switzerland and Liechtenstein will go up from October 1.
But the carriers said they would continue to make available the current lower fares after those dates.
These will be called "preferred fares" and will be subject to the surcharge if booked through a GDS.
Lufthansa will charge agencies €4.90 plus VAT per coupon and SWISS will charge CHF8 (€5) per booking.
If the preferred fares are booked through the two carriers' travel agent portals, or direct from the airlines' websites, call centres or ticket counters, there will be no fee.
Agents' associations in Germany, Switzerland and Austria have urged their members not to sign up to the scheme. The German travel managers' association, VDR also opposes the scheme.
Mr Wilbers said the fee for booking through a GDS would make prices much more complex by adding an extra line to the invoice.
"It will mean more accounting and more VAT and will become a more complex and more expensive to deal with," he said.
He said if Lufthansa and BA both charged the same price for a return trip to London and a company had a policy of picking the cheapest fare, it would choose BA because there was no extra fee.
"This would become an avalnche and Lufthansa would be forced to change its price. It would have to match its fares with BA's but clietns would still have to pay the additional GDS fee.
“Look at the market mechanics. If agents refuse to sign up for the Preferred Fare Programme, Lufthansa would not be able to push through the mark up.
"Any new prices from Lufthansa would be swept away. If the travel agents put their foot down, the companies can be the movers and shakers.
"If Lufthansa tried to force agents to sign, it would be counterproductive. The companies could bank on a strategy of the "best buy."
"My recommendation is that we turn down the preferred price model. I think this price differential is going to go away very quickly,” he said.
Mr Wilbers urged Lufthansa to look at the opt-in scheme now used in both the US and the UK where agents paid a fee of about 50-60 cents rather than €4.90.
BTE approached Lufthansa for a comment but the airline did not respond.