For One Day Internationals
In 320 innings, Inzamam-Ul-Haq has 46 not-outs. Of these, he has 26 not-out half-centuries.
In 339 innings, Sachin Tendulkar has 32 not-outs. Of these, he has 11 not-out half-centuries.
Neither player has scored a century batting lower than number 4 in the order. Inzamam has batted lower than 4th 103 times, Tendulkar, 40 times.
Quite simply, the two players have operated in different roles for their respective teams. It is also signifigantly more difficult to score centuries in one-day cricket batting in the middle-order than opening. Clearly, if you were to assume that both players could have converted their n.o. 50's to 100's at a similar rate, then Inzamam's record is quite comparable to that of Tendulkar's.
i.e.
Inzamam-Ul-Haq: 320 innings, 10 100's + 26 50n.o. = 36
Sachin Tendulkar: 339 innings, 38 100's + 11 50n.o. = 49
Try to stay on topic, it's about Inzi's half-centuries, not his quarter-pounders