If I understand you correctly you are using a repeating group to pull that list of ozmet values? If so you could use “repeating group Xs list of values:each items ozmet:sum”. You could store it in a state and display it.
I think the ozmet column itself is also calculated, so you have to use some format as text trick to calculate the sum.
Simply, your one line formula should be: Repeating Group's Things :format as text :split by(|) :each item :converted to number:sum.
In the format as text box, you have to put the following values (of course, the content to show will be dynamic value):
The logic behind this is: using format as text enables you to calculate some dynamic value for each row in the repating group, more like a map in programming languages but format as text results in a single string combined by the delimiter. Then split by is used to separate the values back into a list.