in fact you may have already started to reduce the power – although that isn’t absolutely necessary yet), you are going to continue
In another life I flew the B737-100 and soon after went on to the 737-200. My check captain (instructor pilot was the parlance in those halycon days) was the original Boeing Seattle pilot who signed off the first Flight Crew Training Manual. His name was Joe Zizovsky who was a US Navy ordance rating during the Battle for Guadacanal. He advised me that the very moment the flare for landing was commenced, the thrust levers must be sharply closed against the stops. He wanted to hear the sound of metal hitting metal with those thrust levers. There was to be no smoothly reducing power - it was whack bang against the stops. The reason (he explained) was that it takes time for the thrust to bleed down after thrust lever closure, and the last thing you want on a landing is superfluous thrust associated with a nicy easy ever so gently pulling back of the thrust levers in an attempt to grease it on. Maybe so in a turbo-prop - but no way in the 737.
Keep in mind that Boeing assume the landing technique is based on a performance limiting runway length - not a 8000 ft highway.
The slow thrust lever closure favoured by many pilots often ensures touch down is further in than ideal and often with the thrust levers still not closed on wheel impact. Not good technique in my book - nor Boeing's if I hazard a guess.