Gnow, I can see from your post that you appear aware that in the EC225, power is protected at the first applicable limit by the AFCS if you use the collective trim switch.
Therefore, the optimum procedure to obtain a robust ROC and ballooning effect off the helideck is;
Establish IGE hover at approx 5 feet. Maintain solid visual references and whilst concentrating of the references press and hold the collective trim down in the aft position. Do not look inside at the FLI as there is no need. The AFCS will protect power at the MTOP. At TDP, (PM call) smoothly transition your references to the FND, 8 degrees nose down, trim release, deploy GA-GA for straight ahead departure.
If operating DLE with an exposure time, at the RTOM, there is a risk of tail strike contact with the deck edge should you become OEI IMMEDIATLEY after TDP. This risk is only managed at the exposure time if the full ballooning effect is achieved. The DLE supplement states an ROC of 500 fpm as the target but do not get misled by the apparent and immediate reading of the IVSI during the initial climb. It responds too quickly to accelerometers before stabilising.
IMHO operating to these offshore performance procedures should to be undertaken with full understanding of the original HAPS model concepts. Power application without exceedance for a high gross mass take off was always problematic. In the EC225/175/160 this problem has been solved bythe AFCS protecting at the first limit in the in coupled mode.
Hope this helps and fly safe.