In short
Tape-out schedule software is believable only if the schedule is driven by evidence: regression and coverage results, the IP vendor's actual delivery, the physical-design milestones in source control, and the fab's shuttle date in the foundry's email. Microsoft Project and Smartsheet hold the plan people typed. Tymeline holds the tape-out date against the evidence and acts when a commitment behind it moves.
Why a typed schedule drifts
A chip program's schedule has hundreds of commitments behind a handful of milestones, and most of them are visible only in the tools: a coverage number that stopped climbing, a timing closure that is taking three runs longer than planned, an IP drop that arrived without a feature. By the time someone edits the Gantt chart, the slip is weeks old.
A schedule held to evidence
Tymeline reads the tools and the mail, so each milestone has a live answer to the question of whether it is still true. When the evidence says a commitment is moving, the dependent work is re-planned the same hour and the fix is in front of its owner. The schedule is a picture of the program as it is, and the tape-out date stays where it was committed.