Academic giant Alliance High School dropped in the 2014 Kenya Certificate of Secondary Education (KCSE) exam results compared to 2013.
Even though the school had one of the best performances in the country, a mean score of 10.85 was a plunge compared to their 2013 score of 11.44.
In 2013, the school had 166 straight As, 77 A-, 22 B+ and 11 Bs while in 2014, the number of As dropped to 123.
In addition, while the lowest grade in 2013 was a B, the class of 2014 had 11 B-, three C+, one C and one C-. It also had 119 A-, 62 B+ and 28 Bs.
The school's principal, David Kariuki, said the institution was content with the results although there have been questions raised.
"I have already heard murmurs and a parent called asking why there was a drop in English where the average was 10.09 compared to 10.97 in 2013," he said.
The principal said last year's drop could be attributed to an increase in the number of students, which strained available resources.
Mr Kariuki said the 2014 class was the largest the school had ever had, increasing from 276 in 2013 to 348 in 2014.
He said handling two extra classes was not any easy task, noting that the school's resources and infrastructure could not accommodate them adequately.
"The ministry just went ahead and gave us an additional two classes we did not have before. We struggled to re-assign teachers and put proper structures in place even though our classes and dormitories were not enough to accommodate the extra burden," he said.
Kariuki also said unlike previous years, the 2014 class had more students from public primary schools.
"We would previously get 60 per cent of our students from private schools and 40 per cent from public schools. Things, however, changed and we got 60 per cent from public schools and 40 per cent from private schools," he said.
He also observed that since most students were not from well-off families, paying school fees became an issue that led to disrupted learning.
"The 2014 class was the first batch to benefit from the free primary education introduced in 2003. These students have made great strides because some could not even speak proper English when they first got here," he said.
The principal said he was opposed to the ban on ranking, saying it would affect performance.
"Candidates' morale will be low because the competitiveness we experienced before is no longer there," he said.