According to email marketing outfit Return Path, games such as Clash of Clans, Candy Crush Saga and Game of Warlook like they are solid performers in terms of their top grossing chart position.
But viewing their performance by analysing their payers demonstrates much more complex behaviour.
For example, between January and March 2015, the number of IAP transactions tracked within Game of War dropped considerably.
However, because individual payers spent more - up 5 percent in February, for example - overall revenues remained steady.
Tides of war
More generally, as these games enter a mature phase, this trend - fewer but bigger spenders - is repeating.
For example, in February the average in-app transaction in Game of War was $67.28, rising to $81.10 in March.
Of course, the most active players are spending much more; Return Path recorded an average of $511.76 across the three month period from the players it surveyed from Game of War.
In a three month period, average spending per payer was $511.76 in Game of War.
This was the most revenue of any game it tracked.
In terms of how it organised the survey, it was generated as part of its regular 4 million-strong email panel, that looked at iTunes purchases for around 18,000 players of games such as Candy Crush, Clash of Clans, Farm Heroes, Game of War, Hay Day and Pet Rescue.
Concentrated spending power
Looking at the behaviour of Clash of Clans players, there was a drop of 12 percent in terms of the numbers of players making in-app purchases during the January-March 2015 period.
The volume of IAP transactions was also down - 27 percent.
For Candy Crush, the fall-off was greater: 15 percent fewer payers and 30 percent fewer IAPs bought.
In both games, the average value of each IAP transaction increased, as committed players paid more, but unlike Game of War, this wasn't enough to overcome the volume decline.
Total spending in Clash of Clans (by players in the survey) was down 3 percent compared to the period October-December 2014.
Candy Crush sales were down 10 percent over the same period, although they were higher in March, demonstrating publishers still have a lot of flexibility to drive revenue with special events and sales.