Necromantic Focus for occultists

[Chess Pwn]

So I have a question about this power. I've heard people say it works 2 different ways and I'm curious which is correct.

Necromantic Focus:

The implement grants its possessor greater power over the undead. Whoever possesses the implement can control an additional 2 Hit Dice of undead for every point of mental focus invested in the item (to a maximum number of Hit Dice equal to 4 × your occultist level). Any spellcaster who bears the implement can add it as an additional focus component for a necromancy spell he casts to create undead. If he does so, he can create an additional number of HD of undead equal to the additional HD the implement allows him to control (apply this effect after doubling the HD of undead for desecrate, if applicable).

one view says that they can create free undead HD when they cast the spell due to the line "he can create an additional number of HD of undead equal to the additional HD the implement allows him to control"

An example of this idea is that if you have 5 mental focus in it to control an extra 10 HD that if you cast animate dead and pay just one HP worth of onyx, that you can raise 11 HD of undead, that the additional undead from using the implement as a focus are free for the spell, and that you can do it with paying nothing, cast the spell paying 0HD worth of onyx and get an additional 10HD for free from your implement letting you cast it 5 times and control 50HD of undead, though none having more than 10HD in this example. And if you are lv10 that you can pay 40hd of onyx and raise a 50hd undead with one cast and desecrate.

The other view says that the implement is just raising the cap you can raise, aka letting you raise an additional amount than normally possible, with the spell but you'd still need to spend the onyx to raise the undead.

an example is a lv10 can control 40HD of undead and with desecrate can raise 40HD of undead with one spell. Now with the implement they raise the cap they can control to 50HD and now they can also raise 50HD from one spell with desecrate, allowing them to raise an additional amount of undead equal to the amount he can control because of the implement.

So which is right or are both "right"?

[graystone]

Hmmm... It raises the cap IMO. Either way, it could have easily been written to be clear [they added desecrate affects after all].

[TrinitysEnd]

I'm with Graystone. It could have been written better, but the wording doesn't mention anything about getting them for free. Which means, even under a strict reading, that while you can create a number of additional HD worth of undead, that you aren't given any permissions to do so without paying the cost.

An example of writing that would allow free HD is:
"If he does so, he can create an additional number of HD of undead equal to the additional HD the implement allows him to control without paying the material cost for these extra HD (apply this effect after doubling the HD of undead for desecrate, if applicable)."

[ShieldLawrence]

So the way I've read it is that creating "an additional number of HD" is saying that it is in addition to the ones you paid for when you cast. And then the line about desecrate is so you don't double the free HD.

I can see the other interpretation too, and would also like clarification.