I do not understand the negotiation that the Rosen corporation does with Rick

I do not understand the negotiation that the Rosen corporation does with Rick

In the book it is mentioned that the Rosen corporation knows that the Nexus-6 androids will be identified by the Voight test. If so, then the production is not closed. Then I do not understand why Eldon is nervous. Rick finds that Rachel is an android. As it did then production will not be closed. But in the book Eldon lies and says that Rachel is not an android, so the negotiation they make seems to me illogical. They tell Rick that they have the recording and they propose that Rick tell his superiors that the test works, why? If it really worked, but I do not understand why they want to make Rick believe it was not. At the end of the day they want the police to know that the test worked, when in fact it was.