How soon does a package need drone comb?

[Albatross]

I installed a package April 16, two weeks ago. I decided to try something new (to me) this year; "Small Cell Foundation" to help with mite control.
I bought some new medium hive bodies, and some PF-120 plastic frames (4.94 mm) from Mann Lake. I put the bees in one medium box with 10 frames of PF-120. When I inspected them today, they were working on six frames. One frame had a section of comb approximately 3" x 1 1/2" built out away from the foundation about 3/8". It was attached at the top, but built out away. On the other side was an undrawn frame. I broke that piece off and took it inside the house to study and I measured it. Every cell on it was just a hair under 1/4" (6.35 mm). I looked up on Mr. Bush's website that drone comb is 6.4 to 6.6 mm. Mine's not quite that big, maybe 6.2 or 6.3 mm, but it's close. They've built comb on the foundation everywhere else.
My question is: How soon does a package need Drone comb? My understanding was that they wouldn't produce Drones until the colony was built up enough that they could "afford to". Are my bees already trying to build Drone comb or do they just hate the plastic foundation? Does the Queen want to lay Drone eggs this early in the game?
I have plenty of medium frames with regular 5.4 mm wax foundation. Should I put one in there to replace one of the undrawn frames?

[MrHappy]

Just a thought, but try putting in a frame of foundationless. That's what I use for my drone cells. I let them build it how ever they what, when they want. I usually put it 4 frames in from the side and they usually make it drones. I let them hatch a few out and then check for Varroa and knock it all out if needed. If they decide after I do that that they need more workers they can make the frame into workers and I can test the size each time they build on it.

Just what I do.