The Collaborative International Dictionary
overcount
overcount \o`ver*count"\, v. t.
To rate too high.
--Shak.To count erroneously, such that the counted number is higher than the actual number.
overcount
overcount \o`ver*count"\, n. A count[1] that is higher than the true number; an erroneously high number determined by counting incorrectly; the result of overcounting[2].
Wiktionary
overcount
vb. To count more of something than are actually present, or to count one thing disproportionately more than another
Usage examples of "overcount".
If, as some say, the messengers have overcounted the strength of the enemy, then I can fight them on even terms.