I think you'll find that the reason that you only came across two census products that provided such information is that the US Census Bureau revised their counting criteria quite regularly in the mid 1800s...especially in regard to slaves.
Those who were rightly saying that slavery was not at all unusual in the north were not referring to the extremely limited time slot you've referred to with your pasted Census page, but to the last half of the 1700s, in which slavery was much less limited in geography.
Those who were rightly saying that slavery was not at all unusual in the north were not referring to the extremely limited time slot you've referred to with your pasted Census page, but to the last half of the 1700s, in which slavery was much less limited in geography.But still much less prevalent than in the south. Look at the 1800 census. There were six northern states which had slaves in that year, but which had ended slavery by 1860. The total number of slaves in those six states was 36,181. By contrast, Virginia alone had 346,671, and the future Confederate states (that existed in 1800) had almost 700,000. The figures for 1790 aren't much different.