HFM - Change member property IsCalculated to Y - data loss expected?

Hello,

We recently amended some of our accounts & custom member property IsCalculated to 'Y'. It was N earlier. These were members where we directly loaded data.

Our understanding was, once a member property is changed to IsCalculated , data associated to that should be blanked out. However, data isnt .

We ran calculation, consolidations and data hasnt cleared out. Historical loaded data still remains there. There is no mention of this data in the HFM rules file.

I wanted to ask -is it recommended to change this property to Y ? I would have thought it causes data loss. More importantly, why didnt data disappear?