cause for alarm ?
I appreciate your post but I'm not sure it is necessarily cause for concern.
The manufacturers set 'check/adjust' intervals based on relatively worst-case scenarios and finding vales that have less clearance than 'spec' does not mean the valve/vavle seats are in danger of damage.
The manufacturer sets the specs based on the premise that some valve seat wear occurs, and that when a bike is serviced, the owner can anticipate some valves will need shims. I would be concerned only if a valve has no remaining clearance.
Have owned circa '65 Suzuki 150 street bike, '78 650 Yamaha, '78 KZ650, '80 KZ750, '81 750K Honda, '82 Suzuki 850G, '70 TR650 Triumph, '74 650 Bonneville, '83 Yamaha YZ250, '95 GPZ1100, '79 Triumph T140, '95 Honda CB1000, '02 FZ-1, '04DL1000