Performing PWCs will not slow a cycle... they are wrong. Nitrifying bacteria do not float around in the water... they live on surfaces, especially the biological media in your filter. It is a common misconception in the industry that PWCs will stall a cycle, that you cannot change large amounts of water at the same time, etc. They are all false. They are perpetuated among many employees who have never actually cycled a tank. A lot of fish stores all run off the same central filtration, so there is no need to cycle a "new tank". You won't find many people who have been maintaining their OWN tanks for many many years who would come close to agreeing with those misconceptions. I myself keep some of the most sensitive freshwater animals you can keep, and change the water at least 50% once a week, and often more than that. It is a small tank... so if the water changes were bad, they would effect the tank very quickly being that it is minimal volume. The science says so long as the water you are adding is ok (dechlorinated, does not contain excessive TDS, ammonia, or PO4) then changing it often is the healthiest thing you can do.
The ammonia is an issue. Are you both using API liquid test kits?