Many "newer" flybacks had a bleeder resistor. So what you are seeing indicates you have one of those flybacks, as evidenced by the fact it drains over time. But the earliest flybacks in the Mac 128k and 512k did not have the bleeder. Hence for some people, discharge is more of an issue. But again, just use the Tom Lee method of full brightness and then a power cord yank. If you practice that you'll never go wrong. That's sometimes important because the bleeder type flybacks don't bleed "instantly." And if you're working with the machine, powering it up and then wanting to work inside, the bleeder wouldn't have had time to discharge the CRT, so you'd need to do that yourself with Tom's method.