I've never used HE detergents in the FL's that I have for a couple reasons:
One, long before HE detergents came out, manufacturers recommended simply using a lesser amount in a FL. If that worked from 1947 until the mid-1990's, then it must still work.
Two, using less detergent obviously is more economical. If a 42 load box can last for 84 or more washloads, that is more money in my pocket (money I can spend washing in hot more often!).
Three, "IF" an HE detergent is a basically the same as regular detergent with a suds-supressing agent in it (which I believe it is), then when it is added to the small amount of water in a FL, the solution is too concentrated and causes fabric weakness, damage and premature wear. I beleive that this is the cause of people mysteriously getting pin holes in their t-shirts, and that clothes feel rougher or stiff coming out of the dryer. The little bit of water used in 3-4 rinses is not enough to rinse out the detergent in modern machines -- suds or no suds.
Four, HE or not, if manufacturers of detergents and washing machines were really serious that HE detergents are so necessary, they would have introduced coin-vend sizes for coin laundries. That has yet to happen.
The only case I see for HE detergents is maybe in a washer that relies on recirculating water to clean the clothes (Calypso). The reason I say this is because the pump impeller is rotating at such a speed to draw both the wash solution and air into it and whip it up like a blender into shaving cream consistancy. An HE detergent used in the proper amount will curb this -- or at least kill the suds when the pump turns off. But then the HE detergent is used as more of a machine protecting additive than it is a dirt removing additive.
Last, the proper amount for a normal washload is up to the first line in the cap or scoop -- approximately 1/2 the full measure. Most people (not the people who post here) use a full cap or scoop. Again, too much is used. I wish manufacturers would make the cap or scoop the RIGHT SIZE and use more if needed.