UPDATED: Qty<1 on BOM shows item not found in pricelist (but =1 is OK)

I have several products which a simply smaller repackaged versions.
I buy material is 25kg bags (but for the sake of simplicity I have set everything to be purchased in kg - so if I buy 2x25kg bags, the PO- simply shows buy=50kg)

  1. I have the material in the “Standard buying” pricelist @ say 200/kg
  2. I create a sales item which sells in units…eg. SOMETHING-1kg (unit)

All OK.

Now I create the “smaller” version
3. I create a sales item which sells in units…eg. SOMETHING-200g (unit)

FAILS with the error/message something like “Price not found for item SOMETHING in price-list Standard Buying”

I have many such items which all seem to work OK, but (it seems) randomly when I create a new one, it doesn’t work. Yesterday, using the exact same methodology, I created 3 such items+variants, but today on this one, it is again failing.

They seem (to me anyway) to be identical in logic…only the 1 line qty is any different, and yet they behave erratically

Any hints welcomed.

I created a UOM of grams:kg and used the grams for the BOM - which is working.
I have NO idea why all the other similar BOMs work using 0.x kg instead of x grams while this one doesn’t, but it’s now workable