Recipe design only allows yeast to be added in packages?

Hi,

I just purchased Beersmith today. It looks great for our brewery, but the one thing I struggle with in the beer design tab is the fact that yeast can only be added in pkg (packages?) and not in grams or ml (or the imperial counterpart).
Is this right, or have I been overlooking something?
Simple example; I make a 220 litre brew at 1059 OG, I calculated I would need 150g of yeast. This is only a part of a 500g pack.
Many thanks for your help.

For my recovered yeast, I define a 'pkg' as being on ml of yeast slurry.  I change the name of the yeast to reflect a 'repitch' yeast and define the active cells of a repitch pkg as being about 3 billion cells.