Until 1781, humans had believed there to be only six planets (including Earth) in the solar system. Although many eminent astronomers had previously spotted the planet Uranus, they had always presumed it to be just another star and listed it as such.
In March 1781, William Herschel made a series of parallax observations through his telescope and believed he had discovered a comet. On 26th April that year, he reported his find. Only after feedback on his report from the Astronomer Royal and independent confirmation from European astronomers, did he finally concede he had discovered a new planet. After some discussion, Berlin astronomer, Johann Elert Bode, named the planet Uranus.
Herschel brought the number of planets in the solar system to seven. Later, Alex Bouvard noticed some unexpected perturbations in Uranus’s orbit and predicted the existence of yet another planet. Johann Galle visually confirmed Neptune’s presence in September 1846 and brought the number of planets to eight.
No, they didn’t! None of those people increased the number planets at all. They were simply the first people to see and catalogue the ‘new’ ones. For thousands, if not billions, of years, the number of planetary-sized rocks orbiting our sun has been eight. You might argue about the definition of ‘planetary-sized’ but according to the current definition, that number is eight, has always been eight, and is likely to remain eight until an astronomical catastrophe occurs.
Similarly, your project didn’t change from a six-month project into a three-year project. Herschel, et al didn’t launch new planets into space and nobody came along and invented new requirements for your project. All of these things existed from the beginning.
Your project is like astronomy. In its early days, none of the participants had the skills or technology to identify all of the planets. Sorry, I mean requirements. That doesn’t mean they weren’t there. It simply means you didn’t know about them.
Now, we have better knowledge and tools and we’ve used them to look at your project. We’ve discovered some stuff those early pioneers missed but thankfully, we’ve found it now.
Aside from the Geocentrics and possibly the Flat-Earth Society, I imagine most people of the eighteenth and nineteenth centuries welcomed the new knowledge that expanded the number of known planets. The discoverers of those planets reaped handsome rewards as heroes of science.
Compare this with the individuals that discover the hitherto unknown requirements in your project.
Will you treat them as the heroes they undoubtedly are and reward them for expanding your knowledge of the known requirements?