How to apply a formula in a Sub-Items table?

I have a 'Sub-Items' column, which is intended to hold a small table of entries:

Service (Text)
Hours (Number)
Rate (Currency)
==> TOTAL (Formula) = Hours * Rate

I've discovered that SmartSuite does not provide for us to apply Formula fields into Sub-Items col.

Can anyone advise, therefore, how I can generate the 'Total' computation in this scenario?

Many thanks in advance.
David

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2 replies