When we got our first Cyclo planter it was an 8-30 We ran a 6-30 head and a 8-30 planter for years.  A change in operation caused us to need more capacity, so we went to a 16-30 planter and got the 1480 with an 8-30 head.  20 years later my cousin split off on his own, cutting acreage in half.  1480 was traded for the 2166 still using 8-30's.  Dad decided the 8-30 head was worn out and traded for the 6-30.  We were still running a 16-30 planter, planting corn and soybeans in 30" rows.

He said we could drive faster and run the same acres per day.  He was right.  He was running 3 MPH with the 8 row and went to 4 MPH with the 6 row.  Since then we have gone to narrow row soybeans and replaced the 16-30 Cyclo with a 12-30 JD vac.  I thought my dragging the green planter on the place might cause heart failure, but he survived. (The last green planter left the place about 1965)

Why 12 instead of 16?  Why not?  I can get everything done timely (There have been very few days the last few years I could plant a full day.  I am usually catching up to the dry ground by the end of the day).  The Vac does a lot better job of spacing (let's not wonder off on that rabbit trail in this thread).  And it was a better planter for growing seed corn production.

To show how rapidly things can change, I mentioned raising seed corn.  At the time we went 12 we were the only growers in the area running 16 row equipment.   Now we are the only ones not running 16.

I have no problem with a running a 6 row head behind a 16 row planter or an 8 row head behind a 12 row planter.  Even our fields that are not flat are not planted on contour, it really isn't a big issue for us.  Would be even less of an issue if the son-in-law drove the planter.  My guess rows sometime make it easy to figure out where to turn in at.  Maybe at 6 MPH I would get more ear loss from row alignment, but at the speeds we were running at the time it was not an issue.

But back to a direct answer to the question:  No. Planter had nothing to do with it.  It was based on the idea you can run just as many acres a day through the 6 as the 8 so why carry the weight and maintain 2 more rows?