I had some questions about developer SPUR ACUROL-N

At spur-photo.com they present marketing info which says,

"At high dilutions, long developing times and reduced agitation, a distinct Eberhard
effect provides for maximum sharpness of contours and maximum plasticity"

The data sheet says,
"SPUR ACUROL-N responds far more easily to changes in agitation than conventional developers. It is therefore necessary to
adhere rather closely to the indicated inversion tact and developing times when using low dilutions (1+25 to 1+50). Otherwise the
lights turn out too steep, thereby impairing tonal values."
"The higher the dilution and the less agitation (e.g. stand development of 5 minutes), the more sculptural the image expression and
the more acutance (Eberhard effect)."

but it also says,
"The developing parameters indicated in the developing chart were determined using 35 mm films. With larger formats, and above
all high dilutions (1+100 or higher) you must increase agitation or prolong development. Rule of thumb: Agitate twice as much as
usual when developing roll film (i.e. invert twice instead of once) and thrice as much when developing sheet film (i.e. invert three
times instead of once). The reason for this is that due to the larger format, and especially with high dilutions, the capacity of the
working solution decreases more rapidly during inversion."

It has a chart that gives processing for Ilford HP5+ at a dillution of 1+100, 24 deg C "Inversion Tact - 30 sec permanently and once every 5 minutes thereafter", developing time 25.5 minutes

Maybe this is a translation issue but I assume "Tact" refers to protocol, and inversion means physical inversion of the developing tank. My LF negatives are processed on hangers in an open top tank. I see reference to the fact that the type of agitation is important. So, jiggling a hanger might not be equivalent to inverting a tank.

1. Does anyone have thoughts on what open tank agitation might correspond to one inversion?
2. How to understand "the capacity of the working solution decreases more rapidly during inversion."? Why would that imply you should agitate more? Are they simply saying, the developer needs to be mixed more, since its "capacity" or potency near the film is low?
3. A more basic question, is this a 1-shot developer, i.e., do you use it once and discard?