That's pretty much true:
1 cup of water = ~ 236 grams
1 cup of flour = ~127 gram*
236 ÷ 127 = 1.85 or 185%.
Problem: people do not measure a cup of flour consistently. Depending on who and how the cup is filled, you could see from 99 to 180 grams of flour in that same cup. Even by the same person measuring a cup one after the other using the exact same technique, there will be inconsistencies. Has the flour been packed down? Do you scoop directly from the bag? Do you spoon the flour into the cup? Do you shake the cup level? Do you scrape the extra off the cup? Has the flour been sitting in the bag for a long time? Do you stir/whisk the flour in the bag first?
And this is aside from the problem of "precisely what size is that cup?" US or UK or AU? Liquid cup or solid volume ("avoirdupois
") cup? And was that cup accurate to begin with? Not all manufacturers are as precise as the next.
Using an accurate scale, however, if you get 127 grams of flour, you have 127 grams of flour, whether that is fluffy or packed flour. You won't have 125 grams or 129 grams, you'll have exactly 127 grams. There is little room for ambiguity.
Fun with measuring.
* Ambiguity creeps in here only because there is not set common agreement on what "a cup" of flour weighs.
Here, I'm going with 1 cup of flour (bread or AP) = 4.5 oz = 127 grams