Using a capacity hat(s) to improve efficiency

The radiation efficiency of the Hi-Q 5/160 antenna is as follows and is based on a 102" whip mounted directly above the loading coil.

160m 1.3%
80m 12%
60m 28%**
40m 43%
30m 60%**
20m 77%
** The Hi-Q site does not quote RE figures for 60/30m so I have taken an average.

Taking 160m as an example this means that for an input of 100w, 98.7w is being lost leaving 1.3w available to do the work - qrp indeed. If you're interested in qrpp just input 10w and this will produce 130mW !!

Leaving aside the ground losses, another major source of loss is in the loading coil which, in order to obtain resonance on 1.836, needs virtually the whole coil in play (maximum inductance).

The HiQ site mentions how effective the EB8 capacity hat is so I thought I'd check it out for myself.

(a) Using just the 102" whip I obtain resonance on 1.836 with a coil setting of 30 (MFJ-1924 controller) which is nearly maximum inductance.

(b) Adding a 1ft extn rod, and an EB8 with whip on top moves the coil setting to 145

(c) Adding another 1ft rod gives further improvement to 154

(d) Adding another EB8 1ft above the first together with the whip gives even further improvement to 193 on the controller.

So, all in all, there is a reduction of 163 turns in the number required to maintain resonance on 1.836 between the whip on its own and adding two EB8 capacity hats. In theory this improvement should translate into improved radiation efficiency (quoted as 1.3% for 160 using just the whip) but I'm not sure how to go about checking this.

The figure in brackets represents the % of the coil being used with each addition of capacity hat. On 160m there is a reduction of approx 50% between the whip on its own (93%) and two EB8 hats (55%).

So, adding capacity at various positions above the coil has resulted in a 50% reduction in the number of turns (inductance) required to maintain resonance on 1.836 - does this also result in a 50% increase in efficiency as well?