My estimate of $141 BILLION was based on a $40/bbl deficit. Make it $60/bbl and it becomes $211 BILLION deficit a year.
Another $10/bbl drop in price would mean another $35 BILLION a year in deficit.
I've recently read that it was estimated that SA has about $900 Billion in cash reserves.
If we use your numbers of +$100/bbl need and see oil drop another $10/bbl, we could watch SA have a deficit of $21 BILLION A MONTH.
That eats into cash reserves rather quickly. In a little over 3 years time their reserves would be gone.
3 years might be a little ways away, but this dropping in oil has been going on for 6 months already.
I guarantee the bean counters are noticing.
3 years at this price will have Iran at war, Venezuela in rubble, and world demand over 100 MMBPD.