Days since an account's last qualifying touch divided by its tier's cadence interval. Over one is past cadence. Beside the order ratio, days since last order over the account's own order cadence, it gives four readings: covered and buying, buying untouched, touched and not buying, neither.
Sorted by days, the quarterly accounts are first every week. Sorted by ratio, the unusual silence is.
Tier cadence for touches; own cadence for orders. Same recency, different expected interval.
Days since the account's last qualifying touch divided by the cadence interval its tier is owed.
A tier A account owed a touch every 30 days was last touched 74 days ago: a ratio of 2.5. Sorting by ratio times revenue gives the call list.
Days since last touch used alone. Sixty days is late for a top account and early for the tail.