This is the lamp I found in the Night Sentry. The ballast in that fixture was an H39 so it was underdriven. I'm not sure if it was put in when the fixture was originally installed or if it was a replacement installed later, or why it was mismatched.
Somebody probably thought they could get MORE light LOL. Or maybe knew it was mismatched but figured the 1752-250w difference wasn't that significant (It really isn't anyway). I suppose underpowered is better than overpowered though: I hear stories all the time of a 175w lamp in a 400w fixture! (And the lamps that lasted for years like this in nightly use).
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Or maybe knew it was mismatched but figured the 1752-250w difference wasn't that significant (It really isn't anyway). I suppose underpowered is better than overpowered though: I hear stories all the time of a 175w lamp in a 400w fixture! 
(And the lamps that lasted for years like this in nightly use).