aggregate and SNP

recently an interviewer asked wat is the difference between SNP hiuristics and SNP optimizer i said in hiuristics we get single planning result but in SNP optimizer we can change the SNP optimizer profile setting like costs,hard consraint, that way we can get many planning result specific to the settings we hav made and choose the best. but he was not convinced with my answer . What is the rite answer ? I have worked on APO projects but am a APO generalist and am not a specialist .i wish specialist inputs on this

next question was on DP about aggregate and disaggregate ..i said aggregate means cumulative plannning (total) planning for the all the quandities and disaggregate means treating individual quantities that is requirement based .then again he was not convinced

So please help me with rite answer .