Perhaps merely incompletely informed. There was nothing to "say" until Rossi claimed it was a GPT. As far as we know, they may have objected immediately.
I think it's quite hard to believe. If they had immediately objected, the test would not even begun. Rossi says that IH have paid for three reports, written by Penon. If you trust this, can you explain the reason why they did? They found so many problems in the fourth report and none in the others? It's just a question of points of view. You find this scenario more probable:"His first goal was just to get the plant in action. But then he wanted Penon to measure it. At this point the idea formed to make this a GPT, it might not have been the original plan -- or it was. But he know that if he said "GPT," it would spook IH and they probably wouldn't let him install the plant there. So he kept quiet about it. However, he did what he could to set up the Penon protocol to look like the GPT, thinking that later he could claim it was, and by this point he had forgotten all about the legal requirements. He wasn't good with those picky details, this goes back to Italy and his troubles there. The idea that this was a GPT became so strong in his mind that he forgot he was dealing with other people, with different ideas."It is a possible explanation, but you can think about many other options. Another one, for example: Rossi told IH that he was preparing the GPT and they accepted. He didn't write "GPT" on his blog, neither Penon did it in his protocol, but maybe they thought it was not necessary because it was clear to everyone that the test was THAT test. IH used the plant to collect investments, but when the end of the test period was near, they began to change their attitude. So they sent an engineer, they contested the fourth report by Penon and, finally, they have made it clear to Rossi that they would not pay him.This is just another way to see the whole story, just another point of view. Maybe not the most credible one, but surely not worse than yours. Just to say that we don't know what really happened, so it's quite worthless take one version for the real one.