To be fair I do not think "better guesstimate" than whatever you prefer to use to compare can quite cut it either. CIG´s own released info has shown lacking quite often. Hugely so in many cases.
Here you have one of the latest examples suggesting CIG´s own published info is probably as unreliable as any other rumorology you can find here or elsewhere. Similarly there is so far no evidence either that CIG´s statements about their finances are anywhere as accurate as we would like them to be.
For example and as a start the financial info lacks fundamental standard reporting elements such as a balance sheet for the parent allowing you to see things like debt outstanding and other liabilities etc, or an actual auditor sign off following recognised procedures and without which it is hard to ascertain the actual validity and source of some of the figures, among other things.
I do not doubt they indeed have cash inflows. But with the incomplete (and more than likely very biased) info available so far is really not possible to determine there is
"enough cash flow" to avoid any kind of loss of control (partial or full) in the project at some point as you suggest I am afraid.