PoppyPaul,
People here report a number of "differences" in how their doctors treat and advise about BCG. This has been my experience also. In practice, I have found that there is NO universal standard that is routinely applied.
Below I provide a link to an article, "Expert consensus document: Consensus statement on best practice management regarding the use of intravesical immunotherapy with BCG for bladder cancer. Many of the group are well known and respected names in the bladder cancer field. Unfortunately, when it comes to my or your bladder cancer, we need to go beyond the statistics and find a doctor who will work with us as an individual. Published research can only go so far. That said...
The article is some 62 pages long. The meat is in the first 10 or so pages, ending shortly after the first set of graphs. The article is well organized into sections devoted to specific issues - browse through all of it.
I am in your boat - but a bit further along; I have gone from clear scopes back to cancer 3 times and have gone well past two rounds of BCG. My individual situation has been carefully considered by my care team. Much depends on individual circumstances. Although I would like to avoid the RC, my goal is to live, not to keep the bladder.
Read the article - It covers our questions very well, I found this helpful. I hope it helps you.
www.nature.com/nrurol/journal/v12/n4/full/nrurol.2015.58.html
Best
Jack