Thanks for the math, it exceeds my math skills. An element for consideration is "...flare performed in a fixed time...". If you're descending at a slower airspeed than recommended for the the airplane, It will slow more quickly as the nose is raised to flare - so the time available to flare will be less. If the pilot is highly skilled, it may work, but it otherwise eats into the margins which most pilots need to do a nice landing. It can be the unexpected slowing in a slightly misjudged flare, which leads the pilot to add a last moment burst of power - if it's available....
The key takeaway is that by gliding at a slower than recommended speed, you are reducing your room for error on several sides at the flare. To achieve an acceptable landing, you'll have to judge your flare altitude with greater precision, as once you begin the flare, you won't have reserve energy to pause it to correct for being too high. And this leads to having to perform the flare all the way through to touchdown as one well judged transition.
The increase in G at flare for a slower than recommended speed is as I said, slight. But, that slight increase one of several elements which result in a reduced margin for error. When you combine reduced margins, the effect is multiplied. On the face of it, if you choose to approach the surface power off with less energy (speed) than recommended, the need for pilot skill increases exponentially. Once you try this non recommended technique at altitude, you'll realize that it's a skill not worth building, when simply flying good power idle approach and landings as recommended is a more appropriate skill to build.