Even if we compare it with the most advanced software available today, the major design updates in the P1 mean that it cannot serve as a strong indicator. Additionally, whether it serves as an indicator or not would yield similar results even if the upper-rear fuselage were identical—which means it’s not a reliable indicator either. As humans, we categorize parts of an aircraft based on specific geometric sections, but this approach doesn’t work the same way in the electromagnetic spectrum. We need to consider the platform as a whole; analyzing just a part of the aircraft won’t lead to accurate conclusions.
As I mentioned, it’s still too early to make RCS estimations for the entire design. As far as we know, the ultimate goal is achieving RCS values close to the F-35. Those who set this target are the ones calculating how the entire aircraft will affect the electromagnetic signature, especially in relation to the upper-rear fuselage design.