70% of something is better than 100% of nothing. 100% of nothing is preferable to 70% of "something", if it costs you 90% of "something" to deliver the service

70% of something is better than 100% of nothing. 100% of nothing is preferable to 70% of "something", if it costs you 90% of "something" to deliver the service, and "something" is already the maximum price the market will bear (and Apple will not allow you to increase the "something" only on iOS to compensate for their demands anyway).