OK, I think the British Standard "Commercial" box is 16 by 10 inches, not 17 by 10. (I think the British National Standard hives use 14 by 12 inch frames.) And 56 liters seems to be a typo. I'm not sure how the volume of a single BS commercial hive compares to the volume in single deep, double deep, or deep and a medium hives.The colonies were all in hives consisting of a single “commercial” brood chamber (11 frames each 43.8 x 25.4 cm, vol. 56.4 l), wooden bottom board with mesh floor, inner cover, and telescopic outer cover.
All that aside, how does volume of the hive affect the efficacy of vaporized oxalic acid? A lot of folks overwinter with a double deep hive. How many overwinter with a single deep hive? Will you need to double the amount of oxalic acid used if you use a double deep hive, instead of a single, in order to get the same concentration of oxalic in the air in the hive?
And what condition were the boxes is? Were they brand new boxes? Were they beat up old boxes with holes in them (often holes drilled by beekeepers)? I've heard you are supposed to try to seal all hive entrances with tape. How much does it affect efficacy if your boxes have plenty of "ventilation"?
Disclaimer - I've never used oxalic acid in any form in my hives. (I have used formic acid MAQS before.) I run my hives as Langstroth single deeps with an excluder for honey production. I place 2 or 3 shallow honey supers under the brood box for overwintering. "Usually" my bees will fill the deep with honey or syrup for overwintering, and the shallow supers are used more for clustering space and dead air space. The majority of my boxes were previously owned, and range in condition from good boxes to pretty rough. Most have holes.
I don't monitor for varroa. I currently use a rotation of one single strip of Apivar, Apistan, and MAQS in the spring and fall. Last year's winter losses were about 5% but over the past few years, winter losses are often about 20%. (Last winter was mild - or maybe I am becoming a better beekeeper.) Before I started treating for mites around 2010, losses were normally 40%-70% every winter.
I don't currently use oxalic acid, but have considered adding it to the rotation of mite treatments I use.