Plein air or not?

Last week I was preparing some panels and I noticed out the window that the sun was shining on the silos to the north. There were great shadow against the grain where some of the corn had been harvested and some was still standing(actually quite a few acres). So I hurried and set up my easel, grabbed a palette with paint globs and painted the scene. I found out with a brilliant day outside and a dark inside, it was very hard to even see the paint I mixed. I felt like I was painting blindly, but I didn't want to turn on the lights because I don't know if the bulbs are warm or cool. This was not my studio room. I finished the painting and it's okay. Somehow , I lost my darks and if I was to paint it  on a larger canvas would have to make some changes . So, did I really paint plein air , since I was inside looking out, or did I do a "studio painting"? or did I do a studio plein air?
I have read other painters doing the same scene over a length of time-a month, a year etc. A scene they see out their studio window-and I assumed they painted it from inside, but  maybe they still went outside and set up under/in front of their window...........because if you paint from inside you do have the glass to consider-it alters the color because the light/color has to pass through it, but how much? And does it alter the tone passing through glass-it must be a little darker. And also our windows have permanent screens, so of course that causes a value shift from the actual tone and would grey down the color also.
If there are any more nice days I think I will experiment. I'll prepare 2 canvases for the same scene-one from a first story window and paint the scene from the inside and then paint the scene outside and hope the sun doesn't change drastically before I can get out and set up. Of course, if I pick a typical Michigan day it'll be cloudy as we advance into November so there shouldn't be too much altering in contrast between painting inside and getting outside. That is the downside of living near the Great Lakes. Many, many, cloudy days.
A reminder-when you go plein air painting have a check list . I did not and congratulated myself on packing everything and not needing one. I scouted the site-my friend's farm yard, taking reference photos, deciding on the best place to set up  -an interesting view with contrast, and an area I could set up in the shade. Yes, I had it all, ......................except odorless mineral spirits. The last thing I was  going to pack and what I left behind. ......so I did not paint, and haven't had the combination of weather, the right time etc to get back.
But first, I need to find the time to make that checklist..........................