Pricing Road Races

The Berlin Half Marathon charges €30 to each of the first 5,000 registrants, €35 for the next 10,000, €40 for the next 10,000 and €45 for the next 2,500, at which time registration closes.  This pricing strategy is new to me:  in the more than 100 road races I’ve done, including one in Europe, a fixed entry fee is charged that jumps up shortly before the race date.  Why the difference?  I don’t think this pricing mechanism is playing off demand elasticities: those who register earliest would be the most avid, low demand-elasticity runners. I don’t see the purpose of what is to me a novel pricing strategy for road races.