Nope, sometimes they normally release fund to you before 21 days (verse-versa)
sometimes, they release the first fund on hold if, you made a second third sales
Contrary to what most people believe, there is no specific parameter when it comes toto this.
You can have a 5 years ebay account selling electronics products, suddenly if, you switch to selling digital items ofcourse, this will trigger the ebay security alarm and fund associated to this transansaction could go on hold.
So, i suggest, you should focus more on selling,shipping,ensure package is delivered to your customer's in a timely manner and you will have no problem getting your money.
Thanks