I have not seen the drawing of Ki-62 in Docavia, but I think it is from the same source. The first published drawing of Ki-62 was on the book "世界航空機三面図集 第3集" (World aircraft scale plans set, vol.3) (published in 1955, Hobun shorin), at page 119. I don't know the original source of this drawing, but I think this is the only drawing of Ki-62 known till today. It is written as ".. a heavy fighter equipped with Ha-140 engine. No information left and the details are unknown. This drawing is said to be the sketch of Ki-62 (imaginary picture of completed one)."
Regards,
Ryusuke