Changing the shot total scales expected counts after the observed probabilities are fixed. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Shot totals scale counts after probabilities are fixed
The true state and assignment matrix stay fixed. The observed probabilities are computed once, then shot totals scale expected counts.
pobs=(2013,207)
Three shot totals keep the same observed fractions
The first two columns stay fixed across the scan. Only the count columns scale with the number of shots.