I would have to say that top soil is not equal.
Think for a moment about a river delta region vs your yard. Or a cow pasture vs your yard. Or a forest area vs all the others. The top soil from each of these areas, would not be exactly the same.
However, my gut instinct would be that whatever top soil you buy from your local Walmart, Lowes, or Home Depot will probably be very similar, so I wouldn’t sweat it.
Maybe you should just set the bags of dirt on the cover and open the tops and plant them for the produce that needs some depth.
Thanks for the suggestions. Just as all top soil is not equal, each garden is not equal, so I have to do it another way than most. The bags for deep roots would fix that problem.