Battery Cycles is not an indicator of battery health except when the Battery Cycle gets near 1,000 cycles which indicates the likely end of life for the battery, otherwise just ignore the Battery Cycles. Apple may also use the Battery Cycle Count to determine if a battery qualifies for warranty coverage.
Batteries run on a chemical reactions and with Lithium-ion batteries this is a very delicate balance where a lot of things affect battery health. The battery temperature plays a role (even when storing the laptops) as does every bump of the laptop which could possibly affect the delicate internal connections within the battery cells. Having a Lithium-ion battery completely discharged for any length of time can weaken and even damage a Lithium-ion battery. Then of course there can always be random glitches in manufacturing or materials (even a bit of dust during manufacturing can begin to introduce a potential premature failure).
"Service Battery" usually indicates a hardware issue has been detected, but this condition has been replaced by a more generic "Service Recommended" beginning with an update patch to macOS 10.15 Catalina which also indicates a "consumed" battery which has a capacity of less than 80% of the original Design Capacity.