The amount of Blackfire Microfiber Cleaner I use on a full load of microfibers is generally less than the amount of HE laundry detergent that I use on a full load of clothes.
I am sure you will be fine using the manufacturer's suggested amount.
I've had zero issues with using bf microfiber in my HE washer. The microfiber cleaner doesn't produce a lot of suds like regular wash soap, so using the recommended amount will be perfectly fine.