Other post? So did he have another post discussing this? Is he doing a production run of finger joint boxes?
So stacked "finger joint" shaper cutters (3" to 6" of stacked cutters) cutting stacked (multiple pieces of) stock clamped together, so you cut all fingers of a side on multiple pieces at a time... Commercial grade stackable finger joint shaper cutters (1-1/4" spindle) are spendy ($200 - $250 each), but you save cost in labor/time and long-term tooling costs.
You could do the same by instead of stacked pieces, cut a finger joint profile into a block, before resawing the individual pieces apart. Sawing the pieces would be the wrinkle that would slowdown your production process. If you needed to speed that up, then a gang rip saw to rip multiple pieces at a time.
If you make jigs to clamp the blocks together (and keep them together and square) for the profile tooling, then your tooling setup can stay static (height) for the different pieces, with your jigs built to set the different offsets (height off the table)...
That is assuming your finger joint side is short enough to tool that in one pass on a shaper (3" to 6" depending on the shaper). If taller, then specialty tooling on specialty machines. If around 6".. you're looking at $800-$1000 in cutters and a 7-1/2 3 phase shaper at around $4000 to $5000. But you could many finger joints (and other profiles) cut all day, every day... in mass quantity.
Either way, you set the opposing sides as the same for where the joints start. The adjacent sides to those are just offset, so a separate tooling setup. The sides end up as the same and "interchangeable" as a piece. Pieces would then interchange between boxes. The pieces of the distinct pieces (1/2 of the pairs) are saved as setup guides to use as guides for setting your tooling on all other later pieces. Remember that a box consists of 2 pairs of opposing sides, and a bottom... sometimes 2 more pairs of opposing sides for the sides of a top... and a top.
The production process would also be affected by how the rough lumber comes to you (dimensionally)...