Search/Results page not showing all possible results

This is on a live site, links are included for testing purposes below.

This is a school fundraising site where I have included a search/results page for parents to see how much $ their kids have raised, as well as an administrative search page, which allows my client to search all transactions.

I have one results page, where I can see results when I perform a search, but my client, and some of the parents cannot. here is the page
https://run4fundscolorado.com/antelope/ar-student-search.php - search last name "zeller" (username and PW in PM). If I pull this report, from this page, in FF, IE, Chrome, I see 4 results. My client doesn't see any?

Now, if they pull the admin report (https://run4fundscolorado.com/r4f-team/school-report.php) they can see all 4 transactions.

The other funny thing, is in another school I can see some of the results, but not all of them. Mind you, the identifier for the school is an uneditable field in the add2cart button. go to https://run4fundscolorado.com/ralston/re-student-search.php - search last name "hawley".

In these results, I am seeing 4 results, where if i pull the admin report, i am seeing 8.

This is really strange, not sure what is causing this. It might also be worth noting that my client printed out 1000s of flyers and promo information with each of the schools URL with capitol letters...so i've had to enable mod_speling because i couldn't build redirects for all of the stupid ways people were capitalizing.

What browser is the client using?

you mention the mod_spelling implementation, so it would be worth double checking exactly the address the client is using in terms of the case, are they using a strange case combination to access the search, or exactly the same case as the link you provide?

when performing the search, are they using the enter key to submit or are they using the mouse to click the submit button?

The way mod_speling works, is that if my directory is "www.site.com/jason" and you type "www.site.com/Jason" the server compares what you wrote to the actual files on the server, and delivers the file that is closest. in other words, if you typed in /Jason, the browser would actually read /jason, as that is the directory that actually exists.

There are no printed links to the reports, the only way to access them is to click a link on the site, so everyone is arriving at the same URL as I am.

My client is using IE 9 or 10

I have tested in IE, FF, and chrome

  when performing the search, are they using the enter key to submit or are they using the mouse to click the submit button?  

can you please address my last question?

I don't know, I assume they are clicking search - I must admit, my users aren't tech savvy, I asked which browser they were using and they responded "comcast"....which is their ISP. I've tried both, and it has no affect on the results. I've also sent the url (cut from my browser where results are present) in an email where they would simply click the link, and they weren't able to see the results there either.

  ar-student-search.php - search last name "zeller" If I pull this report, from this page, in FF, IE, Chrome, I see 4 results. My client doesn't see any?" - what do you see?  

I see the 4 results, I Am not able to reproduce what the client sees. perhaps have them try to use a different browser like Fire Fox, or clear the browsers cache.

  re-student-search.php - search last name "hawley".

In these results, I am seeing 4 results, where if i pull the admin report, i am seeing 8.  

on the results page, you have a group by clause for the recordset:
GROUP BY DetailStudentL, DetailStudentF

this group by does not exist on the report page.