Azed 1819

[stephem]

A new azed crossword today so, before I start on it, can I ask for help with the only clue I couldn't understand from last week?
30ac Nurses making (in sum) 1/10 formerly?
T?NDS

I presume the answer is TENDS=nurses but how does the rest of the clue fit in?

[kayakamina]

It is an alternative spelling of teind ( a tithe / tenth)

[stephem]

Oh, thanks for that.

That explains 1/10 but what about 'making (in sum)' and 'formerly' (teind isn't listed as obsolete or archaic)? i needs to be removed (in=i' perhaps?) and replaced by s but I can't see how that is clued.

[stephem]

Peter Biddlecombe on the Fifteensquared blog gives a different explanation:
30 TENDS - (ten d., s.) which would be 1/10 in LSD.
so that's why 1/10 was used instead of 'one-tenth' as it means the old one and tenpence. I thought of d=old penny but never got far enough to make the clue work.