change base unit of measure

Dear all,

I have changed the base unit of measure in Material master MM02, from Gram to Liter.

then i create PR , after that I convert the PR to PO , but there is an error message says that Base unit G cannot convert to base unit L of requisition.

Info record exists for this material. and i can see there the order unit is still using G. should I change it ?? any effect if i change it? or should I create new material?

One more question

Is info record always created automatically if I checked the indicator info update in ME23n?