The DPRK's new launch, Hwasong-15 or something bigger?

According to recent news reports, the DPRK was suspected of preparing a launch of the giant ICBM they unveiled during a parade in October 2020. I tend to call it the Hwasong-XX because its actual designation is unknown.

This morning a new launch was indeed reported. According to the South-Korean MoD, the missile flew a distance of 1080 km and reached an altitude of 6200 km, landing off the coast of Aomori prefecture, Japan. This trajectory is highly lofted, similar to previous launches, but with a higher apogee. The previous record was set in November of 2017, when they launched their then-new Hwasong-15. This flew a distance of 960 km and reached an altitude of 4500 km. As I write this, I have yet to see footage of the launch, but the increased performance during the latest launch suggests that, indeed, it may have been the Hwasong-XX.

However, there may be an alternative. In the past the DPRK has launched missiles on such extremely lofted trajectories by reducing the payload. This raises the question whether this could have been a lightened Hwasong-15 rather than a Hwasong-XX. So, I have run some simulations. My Hwasong-15 model can reproduce the 2017 trajectory with an RV mass of ~560 kg, but it can also reproduce the new trajectory, with its RV mass reduced to 180 kg. This leaves little more than a heatshield, but it is certainly possible. So, unless footage of the launch shows the Hwasong-XX, right now I cannot rule out that this was a Hwasong-15.