The acetaldehyde issue is discussed in many wine research papers. I generally go with Clark Smith or the AWRI.
"Apart from chemical and microbiological formation, winemaking practices can influence the level of acetaldehyde present in wine; addition of SO2 during fermentation can increase the concentration of acetaldehyde, as can increases in pH and fermentation temperature."
A range of taints, faults and flavours are commonly encountered in wine.
"Addition of SO2 in the presence of active yeast will lead to the formation of SO2binders. For every 10 mg/l of SO2 added to the must, bound SO2 levels in the final wine will increase by 3-7 mg/l." Sulphur Dioxide Content of Wines: the Role of Winemaking and Carbonyl Compounds, Cornell University Research Focus 2011-3
"Winemakers divide themselves into two valid camps depending on their terroirs and goals: the Green Juice Club (30 ppm at the crusher for healthy fruit) and the Brown Juice Club (nothing at the crusher).
Bisulfite also binds to aldehydes, principally acetaldehyde, which is the penultimate enzymatic step in fermentation just prior to its ethanol endpoint. As a result, all sulfur dioxide added at the crusher and created by yeasts during fermentation is bound; none is free at the end of fermentation. In fact, the more you add, the more you create an aldehyde pool, necessitating increased addition later. To obtain 25 ppm free SO2 post-fermentation, Green Juice Club members typically add 70 ppm, whereas Brown Juice Club members need only add 50 ppm."
Sulfur Dioxide Basics Revisited, Wines & Vines March 2012 by Clark Smith
I agree, ask 10 winemakers get 20 answers, I'm sure it is an issue of degree, adding SO2 at the end isn't as much of an issue compared to addition at the beginning of fermentation or mid-fermentation. However, the only time I've seen a recommendation to add SO2 near the end of fermentation was in reference to potential bacterial spoilage, that is if Lactobacillus cell counts start rising. Knowing and Making Wine by Emile Peynaud 1984