No, what you describe is hairline to end, if I'm not mistaken. The way to measure hairline to end is to brush your hair back. Then you hold the zero mark of a tape measure against your hairline above the center of your forehead with your finger then with your free hand you stretch the tape measure against your hair over your crown all the way to the ends of your hair (stretched, if natural) on that central plane. In other words, make sure you don't go diagonal, if you want an accurate measurement. Keep the tape measure centered all the way back. You may need someone to help trace your hair all the way back and mark where your hair ends on the tape measure (by pinching the mark )if you hand can't reach back to the ends of your hair.
For scalp to end measure (how I like to measure my hair), I use a ruler, preferably one whose zero mark is at the end so I know I'm getting the exact length from base. But it isn't such a big difference if the zero mark is a little bit inside from the end. I then hold a few strands of hair straight up (think porcupine) and hold the ruler (the end the numbers start on against my scalp) and I hold my hair along side the ruler (sorta press it along the ruler stretched). I may run my finger along the hair against the ruler just to make sure I there's no slack. I don't pull. I just make sure it's as straight as possible. Then I look in the mirror to see where my hair reaches on the ruler and I pinch the ruler at the point where my hair ends and I don't let go the pinch until I bring the ruler to eye level and read off the number. (You actually don't need a mirror coz you can sorta pinch the ruler around where your fingers feel your hair coming to the end. I prefer the mirror though coz I can ignore the extra fraction of an inch of one or two hairs trying to beat the rest.) I try to make sure the hair I'm holding is a good rep of the rest of my hair. So don't take the longest hair or the shortest. Try a few to get a feel for what's average so you get a realistic picture. I actually like the rulers whose zero mark isn't at the very end coz if I measure 9 inches, then I know it's really a little more than that. But I tell myself it's 9 inches just so that when I do get to measure accurately one day, I'll be pleased.
Plus it allows for split ends should I decide to trim them in a few. Now of course if your hair is longer than your average ruler or your arms,
you might need to lie down and have someone use else stretch twine along your hair while you hold the end against your scalp and then mark where your hair reaches on the twine with a pen (or cut it) and you measure that length. Those of you that fall in this category, I salute you.
How do you measure growth? Well, after a while I will stretch my hair the same way, and take readings the same way. It helps if your hair is fairly even or if you have got it cut a certain style, then you could make a chart: bangs - 4 inches; top of head - 17 inches; back - 14 inches. (Those examples are for measurements from scalp to ends by the way. Hairline to end would be a single much bigger number since you'd start from forehead border (center) all the way back to where your hair reaches when you brush it back.) Now, after a month or so you would take measurements at the same places and if your bangs are 5" and top of your head is 18" and the back is 15"...then you know you had an inch growth. I think someone asked what to do coz hair may be wavy at one time and straight another time. That's why you need to stretch it when you measure. I may be wrong but I think my natural hair stretched will be exactly the same length it would be when relaxed. Or better still, if your hair is relaxed, measure it only after a touch up so you can get a true figure. Then wait until your next touch up to measure again. In other words, measure when it's in the same state each time. Note the dates you took the measurements so you know how long it took to get from one length to the new length.
I hope that answers your question(s).