I think the key point is that at the end of each trading session...

I think the key point is that at the end of each trading session we know (subject to the veracity of data reported to ASIC each day) those shorts remaining (ie the amount of overhang in the stock) and which ultimately will need to be covered at some point by short sellers purchasing shares.
As that short selling position increases which has happened up until recently in the case of CU6 (and unfortunately the 4 day lag for reporting net shorts creates uncertainty in this regard), regardless of whether its an increased exposure by the same short sellers, or by an increasing number of short sellers who may have different trading tactics, ulrimately the exposure becomes increasingly harder to close out.

With the share price decline of CU6 now stalling, and the likelihood of further large share price declines lessened, IMO the shorts are becoming increasingly vulnerable -especially with a quarterly report due by the end of next week (and yes that report could contain good or bad news).