For a 'relatively recent' term it has been around for a very long time! I have found phonics teaching called 'synthetic' in late nineteenth century 'How to Teach Reading' books. I don't think anyone has tried to prove that your results are wrong. Your results are fine and congratulations (though wasn't it meant to be every child a L5 reader?) What I, personally, am querying is your inaccurate and unsubstantiated statements about SP.