Right now SP holders can earn curation rewards from 'content reward pool' to which 65% of the inflation is directed.
Plus SP holders do get 'vesting rewards'( 15% of the inflation)
With 10% for SPS and 10% for witnesses there's nothing left for 'savings'.
What I suggest is SP holders should only get curation rewards from the 'content reward pool'.
The 'vesting rewards' should be paid to 'savings' instead.