Why can't you write programs like this? Do you understand?

Because there must be enough source features to create the plane from (least 3).
PNT1[1..12] is one input feature. Split it up: PNT1[1], PNT1[2], PNT1[3..PNT1.NUMHITS]

I don't think it worked

I don't think it worked

Try .NUMHITS instead of V_COUNT, see if that works

I think the effect is the same, it's the numerical value

WilliamL, I understand what you're trying to express, but I feel like it's a problem with this software version

Now that you have tried everything, I agree. This may be a bug. You may try what I said above, do PNT1[1]..PNT1[12] Or just do each point 1 at a time.

With loops, if you do a construction and select a point, does it show each instance of the point in the window?

     I tried it without any problems in the 2017 version

It will be painful, but try 

CONSTR/PLANE,BF,PNT1[1], PNT1[2], PNT1[3], PNT1[4], PNT1[5], PNT1[6], PNT1[7], PNT1[8], PNT1[9],PNT1[10], PNT1[11], PNT1[12]

To see if it will even work at all.

Brother, of course that's possible

What if you did this? Sorry I keep asking you to test things, I don't have a way to test this.

PNT1[PNT1[1]..PNT1[12]]

Cool, very nice

Brother, I must give you a thumbs up