Regarding the vowel chart: Interesting. I don't know.
I don't think those are central vowels because:
1) There is a substantial distance from the center.
2) They're in very different places from each other, not both at the same "center" location.
Remember that exact locations are not the same from language to language. The best guess based on that vowel chart would be that these are [ɪ] and [ʊ], which just happen to be slightly more centralized than in English. But it's still odd to call them "lax" when they appear long and otherwise not "lax".
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This is very good information, but it is still somewhat limited. Articulatory information would be very helpful.
Please do your best to answer the following questions for each vowel:
1. Look in a mirror. Are your lips rounded like "o" or unrounded like "e"?
Is it possible that these are a rounded front vowel and an unrounded back vowel? Just based on the location in the vowel chart, that might be possible. They didn't sound like that to me, though.
2. Where do you believe your tongue is?
Specifically, compare the unknown back vowel to [u] and the unknown front vowel to [i]: is it the same height? the same tenseness? the same backness?
Although it requires some technical knowledge, this is relatively easy to do and you should be able to at least approximate whether it feels like a different place of articulation.
Additionally, although it would be a lot of work for you (but valuable for your research and also possibly for the broader community of linguists), it would be great to see a full vowel chart-- remove/ignore the English vowels and plot all of the Balochi vowels on a chart. The locations may simply differ from English (so it's not a good idea to compare English [i] to an uknown Balochi vowel!), but the final distribution could be very helpful in determining what the system is, I think.
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Edit: also, as in freknu's posts, I'm concerned about the fact that your data is completely different from what appears in existing descriptions. I know nothing about Balochi, so I am assuming that your data is correct. But there should be some reason why your data differs-- either you're describing a different dialect (entirely possible), or you or the existing analyses are wrong. It would be worthwhile to check on that.