TLC always had lower endurance vs. 2-bit MLC. The numbers simply show that this applies to 3D NAND as well.
I recall when planar TLC first came out, consumer-level MLC NAND was averaging something like 3K P/E cycles. There were even premium/enthusiast products that advertised high quality 5K P/E cycle NAND to differentiate themselves from the rest of the market.
First TLC NAND was rated for about 1K P/E cycles, if I remember correctly, and there were a lot of concerns about endurance.
So, the endurance difference was anywhere between 3x and 5x. The difference between SM863 and PM863 is close to that range, so it looks normal to me. Note that the 10DWPD version of SM863 uses higher OP out-of-the-box, so the ratio is higher there.