GAO/IMTEC-92-26's Appendix II table shows Patriot time-drift growing in direct proportion to run time, from 7 meters at 1 hour to 687 meters at 100 hours

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claim-patriot-dhahran-1991-clock-drift-from-24-bit-truncation-of-tenths records the single figure most often quoted from GAO/IMTEC-92-26 — 0.3433 seconds of time error and a 687-meter range-gate shift after 100 hours of continuous operation. Appendix II of the report ("Effect of Extended Run Time on Patriot Operation") gives the full progression behind that number, confirmed verbatim in a direct re-read of the primary:

The table's own footnotes mark the 20-hour row "target outside range gate" and the 100-hour row as Alpha Battery's actual uptime at Dhahran. The 20-hour threshold is not an independently measured figure: GAO states the shift is "directly proportional to time" and derived 20 hours by extrapolating the Israeli data behind claim-patriot-dhahran-1991-known-bug-patch-arrived-one-day-late — the same 20-percent-shift-at-8-hours reading that reached the Patriot Project Office on February 11, 1991. That the 100-hour drift and the 20-hour "target lost" threshold both derive from one proportionality relationship, rather than two separately measured data points, is the fact this table adds that the single headline figure did not carry on its own.