It’s not easy designing a “DIY” audax route. The way these rides work is that you nominate a series of controls, then you ride around and visit each one in turn, collecting “proof of presence” in the form of receipts or cashpoint slips. The tricky bit is that you only get credit for the shortest distance between each pair of controls. So you pick two nice cafés about 50 km apart, but then it turns out that they are only 40 km apart via the A1, so that’s all you get credit for. Add up all those little diversions, and soon your DIY 200 is actually 240 km.
On a calendar ride, the organizer can put in “information” controls anywhere on the route (or at least, anywhere that it’s possible to ask a question), and so bring the distance ridden closer to the nominal distance. When I ran a calendar event a couple of years ago, with judicious placement of controls I managed to get the distance ridden down to 200 km exactly, and so reasonably friendly for beginners. But that’s not possible on a DIY.