Depending on what you call a "seminar", the CSC organization in the west does have testing requirements that are taught in the form of seminars or special classes, which are taught once or twice a year on a Sunday. Other extra cost classes will last for an entire month, with four sessions that take place before regular Saturday classes each week. These are mainly the forms for advanced black belts, and are always needed for advancement. These extra classes used to be 40-60 dollars depending on how long they lasted, though the price may have gone up now that the basic prices for all classes have gone up pretty much universally. If you've seen a particular class once, it's half price any other time you go to it.
Brown Belt is the first time this happens, and again for all the black belt levels. I chin ching and san he chin are taught together as a special class twice a year, so you need to take that one before your first brown belt test. 37(64) Yang taichi is taught in this way, once or twice a year. Almost everything required to grade from second black and up is taught in the form of special classes that cost extra on top of normal class fees, including all the hsing i material, all but one of the jian forms, all the hua to's qi gong, the hua fist forms, the drunken forms, etc.
This is where that "rumor" must have come from, because it's true. The masters and some teachers might waive fees for students who are having a hard time, and assistant instuctors who can "work it off". But officially, it costs extra to get the advanced material.
"I am a servant of the Secret Fire, wielder of the flame of Anor. The dark fire will not avail you, flame of Udun! Go back to the shadow, you cannot pass!"