Can the old region be largger than the setting of JVM

Question

I have a project with G1.The JVM Parameters are:

    -Xmx12288m 
 -Xms12288m 
 -Xss256k
 -XX:G1NewSizePercent=35
 -XX:G1MaxNewSizePercent=60
 -XX:MaxGCPauseMillis=200
 -XX:+UseG1GC
 -XX:-OmitStackTraceInFastThrow
 -XX:MinHeapFreeRatio=30
 -XX:MaxHeapFreeRatio=50 
 -XX:+UnlockExperimentalVMOptions

There is a youngc with the GC log: 2024-01-25T19:25:58.266+0800: 7483.790: [GC pause (G1 Evacuation Pause) (young) (to-space exhausted), 1.5322861 secs]    [Eden: 6828.0M(6828.0M)->0.0B(4148.0M) Survivors: 272.0M->152.0M Heap: 11993.5M(12288.0M)->9724.0M(12288.0M)]

My heap capacity is 12G(min and max), the G1NewSizePercent is 35%, which means the max capacity of old region is 7987.2M. But the gc log shows the eden was 0 , survivors is 152M, heap is 9724M after younggc.

(1) Is the old region capacity: 9724(total capacity) - 152 (survivors) - 0(eden) = 9572M ? (2) If (1) is correct, why can the old region capacity be larger than 7987.2M?