A no-template control has no threshold cycle in this finite toy ledger. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
The negative control has all-zero counts
With start 0, every checked count stays zero against threshold 64.
0,0,0,0
No crossing uses the fail-closed sentinel
The threshold cycle is -1, crossed bit 0, and accepted bit 0.