You're probably right. But if the Spurs were waiting for the salary cap numbers to be released, then wouldn't Splitter's camp have known about this and if so, why would they be putting pressure on the Spurs to present them with a satisfactory offer?
The optics of this don't look great, but I've got to believe the Spurs front office knows the importance of signing him and will not botch this. The lack of progress is frustrating, but I'd be very surprised if in the next few days they haven't, if not agreed in principal, at least made significant progress in talks.