There's no way I'd use a half dose of detergent in a machine that fills the tub full, regardless of HE formula or not. High-efficiency detergents are designed not to over-suds in low water settings, and to rinse well in low water, but their cleaning concentration isn't changed. Detergent use technically IS halved in an HE machine because if used right, you're cleaning around twice the capacity of clothes than what most any traditional top-loader can handle.
For example, a full load piled loosely to the top of the basket in the 4.8 c.ft Cabrio translates to two full loads filled to the top of the 3.6 c.ft Whirlpool agitator washer, with a full scoop of detergent in both. In the Bravos, that would be plenty for that one large load, but would be two full scoops in the Whirlpool to get the same cleaning, despite the load being split. It's a tradeoff; with the traditional TL you're getting quicker wash times, but at the cost of lower capacity, more water, and the proper dose of detergent to overcome dilution from said water, where the HE machine takes more time but with less water, greater capacity, and the same amount of detergent for around twice the capacity.