It is not entirely clear from the description in metered billing whether it is "locked" completely after app approval or it is just the editing of price/description of an approved metered tier is not allowed.
In other words, if the app is approved with : $0.99 per "foo"
Is it possible to add another metered tier at some point? $0.49 per "bar"
On that same note, if the app is submitted with "$0.49 per bar" disabled initially - is it possible to "enable" it at some point, or does this also fall into the "editing" category?
Obviously merchants would have to be notified of a change and opt in.