I believe it is wrong to try to get a number for growth rates of any paph. Unless it is a very rough number of course.
Let me explain; one thing is that there is a vast variation in growth speeds within a flask, secondly, growth happens in "spurts" where a leaf can grow at a considerable speed. Some year ago, I measured it on a lowii (perhaps it was something else but it is reported here on ST) to be more than 1mm/day. This makes the leaves flip over, and when that growth spurt is finished, they stiffen, and raise and appears normal again. This happens to many (most?) of my multis including roths.
This mode of growing seems not to be a consequence of fertiliser regime as that has changed over the years without much influence on the growth pattern. Now I am at very low fertiliser levels and growt still happens in spurts.
Nothing is wrong with information, it all depends on how you use it.
You just provided a growth spurt of 1mm/day. This is a peak growth and then the growth slows down and stop, while another new leaf is coming out.
You can get an average for this. It's good to have a reference for peak and average growth. If it takes 6 years from flask to flower, I don't want to wait until the sixth year to conclude oppps, I'm not doing right. If I have the info to know the result/s in a month or a week, that's all good.