I wouldn't estimate the difference between the two as "pretty small". Extremely significant in fact. Studies have concluded that the Gulf Stream must have entered the Arctic basin during glaciation and kept some areas ice free. The standard model doesn't account for this as far as I'm aware.Not much. There have always been different estimates considered side by side, but they are pretty similar in broad details.
You may be mislead by the different projections, but the differences in the two glacial extents shown are pretty small. Some differences are not surprising, especially given that there has never been one gold standard extent, but rather various proposals by different researchers.
Cheers -- sylas