on vs since

0Yes, "since" would be better, assuming they did not increase it for only that one day, May 10.0-

0GG, asuming the increase only applied to that particular day, would the sentence still be correct? I guess not. If not, how would you rephrase it by changing as little as possible02br
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00Thanks!0-

0If it applied to only that day, it's correct as written, OR you could use simple past: they increased production on May 10.0-

0GG, thanks for the suggestion of using simple past.02br
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00Since I've come across a sentence which uses perfect tense with a point in the past ('on'), I would like to understand why it's acceptable.02br
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00I was told that perfect tenses don't work with a specific point in the past, for example,02br
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00??I have had lunch at

0Well, first of all, I said that since would be better.02br
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00Second, note that it's PAST perfect, not present perfect.02br
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00We had had a big lunch at 12:30, so I wasn't ready for birthday cake at 2. We had been to his house only yesterday, apparently only shortly before the fire broke out.02br
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00I guess that they are su

0This is something new and big to me. I didn't know that the violation of inserting a time in the past when using perfect tense only applied to PRESENT perfect tense. I thought the rule applied to all types of perfect tenses which is why I gave my examples, examples that I'm confortable with, in present perfect tense.02br
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00Thanks GG!0-