Hold Under Instead Of Hold Over?

I was watching an airgun bird hunting video and noticed this particular hunter zeroed his air rifle at longer distances and held under his quarry for many shots. I think he only had to hold over a half mildot or one mildot for a recorded 90 meter head shot. Watching this video made me think hold under was easier to use than hold over.

My question is this: If you think most of your game will be at least 70 yards in distance, why not zero your airgun at 70 or 80 yards and hold under for the occasional closer target?

Here's a link to the video I was referencing:

 
I kind of do this at times... I have both my .30 and my .25's zero'd at @50 and 65 yards respectively. I find this works for me, because it is the way that I have been shooting them. When switching between them, i have to go out back and take some practice shots to re-acquaint myself with the aim points at various distances. When I get into doing more shooting with more actions, I will most probably wind up re-setting zero to @ 40 yards, and use them like everything else ... so, I do not have to try to remember what is what.
 
Shooting at small targets ;-) I just came in from taking a shot at a chipmunk (you know how small the are). It would have been difficult if I had to figure out hold over/under as quickly as I had to acquire this little target,and take a shot. They don't tend to sit still long! Because I kept him at the distance I have my zero set (@50 yards) I was able to just aim dead on. Squirrels, and ground hogs tend to move slower, and allow time for me to figure hold over/under... by the way, absolutely crushed the chipmunk.
 
The only time it hasn't worked well for me was the time I forgot I had changed the magnification on my scope and picked the gun up for a quick shot on a bird (doh)....With a FFP (first focal plane) it's not a problem but, with a SFP (second focal plane) you either need to make sure you use the correct magnification or account for the change in magnification in your hold. With a SFP scope, objects in the scope will enlarge or shrink with a change in magnification but the reticle does not.
 
My father had a chipmunk infestation. They had torn and used the insulation under his car hood for nesting material. When shooting from the second story of the house down a hill at 23 - 25 yards I used a hold under of 1-1/2 mil-dots. When shooting from the ground level at 12 yards I was using a holdover of 1 mil-dot and when shooting from ground level at 25 yards I was on the crosshair. Versatility is the reason I use a scope with mil-dots. I sight in at the poi that gives me the longest distance in the kill zone and use the mil-dots as needed.