I think you might be taking it to the extreme. Both your posterior and anterior chain should be doing some work if your're doing front squats, high bar, or low bar squats. All muscles should be working to some degree and it changes based on where the loading is place.
Let's say your upper back, abs, glutes and quads are maxed out when hitting 365 high bar. In general when switching to low bar, a person should be capable of handling more weight because the increased loading is offset by the reduced moment arm seen by the upper back and knees (quads). The hip extension demands increase and this is picked up by more hamstring and lower erector recruitment. In summary, all of the muscles in high bar should still be working hard in low bar and the additional help is supplied by greater recruitment in the erectors and hamstrings. If you treat them as completely different movement patterns, you won't get any carryover between the two lifts.
Try making the lifts feel similar, aside from the erectors and hamstrings doing a bit more work.