Your arithmetic is sound, but I guess you would need to have different goals in mind to decide whether its application is appropriate to the problem you presented.
Right now, my reading stats are logged as 3.3 million, but it is realistically closer to 4 or 5 million because I have a lot of Spanish telenovela transcripts loaded into LingQ from Netflix. I read those subtitles when I watched those shows, but only recently has that feature been added to LingQ. I’ll get a better idea what my true number of words read and known are once I finish clearing the blue words, creating LingQs, etc. Let’s say I’m at 4 million now, but I’ll have about 1,600 hours of today Spanish time logged. About 800 of that is listening or listening and reading combined. The other half is just reading, “studying” (grammar etc) speaking and writing. (FYI: “Fluency” seems to happen around 900 or 1,000. ) Maybe if I had spent twice the amount of time ie 1200 hours just reading I’d be up to 12 million or more, but my goal wasn’t just to be an “advanced reader” (whatever that means). I would have to think that anyone who spent that much time reading would be considered advanced by anyone’s definition.
For me, I can read a non-fiction book on a subject I’m interested in with no problems. I haven’t really tried to read someone I’m not interested in. For Spanish novels, I do get a number of unknown words, but I feel that I can still comfortably follow along. I wasn’t just “getting the gist.” I last tested this a year or so ago by reading a chapter or two from La Sombra del Viento. Someone on this forum years ago told me this would happen after 40,000 known words or so and I’ve found that to be true so far. I suspect that when I’m done importing those episodes into LingQ, my Known Words will be closer to 45 or 50K.
Whether I qualify or am just on my way to what you might call “advanced,” I can say that the process I’ve undertaken is the same: lots of reading and listening. Per the suggestion Francisco (ftornay) from a few years ago, I did load a couple of novels I wanted to read in Spanish into LingQ and as promised, my known words did “skyrocket” and I did shoot past LingQs Advanced Level 2/3 of 33,200 known words–both as he promised. I have not tried to do this again because I’ve been off and on trying to finish those episodes. Once I am finished, I’ll be ready to move onto another language because I will be able to do everything I set out to do and more in Spanish.