[css-grid] "Distribute space to base sizes up to growth limits" unclear #3615

From https://drafts.csswg.org/css-grid/#extra-space, "Distribute space to base sizes up to growth limits":

Find the item-incurred increase for each spanned track with an affected size

It's not clear whether "item-incurred increase" is a definition or a reference to some existing concept. I think the former, but it's not clear at first sight. I believe definitions should be in bold italic text, not just italic.

by distributing the space equally among them,

Does "them" refer to the spanned tracks or the affected size? I guess the latter. Also, it can seem this distribution is increasing the affected sizes, while in fact I understand that it goes to the item-incurred increase (and this is its definition).

freezing tracks as their size reaches their growth limit

It's not clear which size this is talking about. I guess it refers to the affected size plus the item-incurred increase.

Note: If the affected size was a growth limit, this step has no effect.

In that case I think the step is still defining "item-incurred increase", which is referenced by later steps. Isn't this an effect? The note could clarify that the "item-incurred increase" is then 0.