if you don't know guaranteed analysis change every now and then and are extremely in accurate you haven't been in the business long.
And no they don't the strictest label laws are in Colorado where you need to be writhing .4% whereas CA you merely need to list above a guaranteed minimum and basically put down whatever you want as long as it's above a threshold.
If you really think I'm wrong please get a lab analysis done on one of your bottles. Seriously any bottle and I'll almost guarantee it's wrong.
My source would be personal experience I have worked in the industry for years selling this stuff. I have talked to damn near every rep that has come through our area talked to a lot of nute co owners and they will straight up tell you it's a label not fact sheet.
For instance
house and garden if you read their base anylisis you have 99% water but we know that isn't true and
advanced nutes has changed their base 3x in the last 8 years but their analysis hasn't changed once.