They didn't test 6 bums.
The Chinese tested their new bum design (possibly a Neutron bomb?), because soon after that the chinese were claiming that they had (acquired) neutorn weapons tech. To which BARC scientists also said that that technology was not unusual or unachievable for BARC.
The Pakistanis tried to test their own bomb a week or so earlier, but it didn't do off, or it didn't go nuclear. Numerous well regarded observers have hinted at this. Then musharraf had to rush to Beijing to request them to preserve H&D, and so the chinese brought their own weapons and tested them. Meanwhile they were scared that the IAF will intercept the shipment midway, so they made that story of IAF planning to attack the test site
The videos of a hillock squiggling are of the first day's test. Again that same evening different pakistani netas, scientists and faujis were saying different things about the number of bombs tested and the yeilds, because these guys were all over TV to take credit. It was laughable because everyone was obviously lying, and with the world watching.
They tested something two days after the first test. That didn't even disturb the seismographs too much, but that site was nevertheless identified as a very low yield explosion 50 odd kms west of the original test site. That probably was the pakistani design that had been re-tested.
So they probably tested between 2-3 devices and 1 chinese device.
1. 1 pakistani device a few days before the actual publicized test - failure
2. 28 May 1998 - Televised test of 1 Chinese device, possibly one Pakistani device tested simultaneously - result the chinese device probably performed as per the expectations of the chinese designers. Pakistani device did not contribute to the yield - ?Failure.
3. 30 May 1998 - 1 Pakistani device tested 2 days later - again failure / very low yield.
Then there were stories of two North Korean transport aircraft that were parked at Chaklala Air force base, Pindi during the entire events. It was speculated that the Chinese device had been brought in by air on these N korean transport planes.
My 2 naya paisa.