The seven kings that died were really ten. The first king corresponds to the four days before (Erev) Pesach, whereas kings two to seven correspond to the first six weeks of the Omer. To reach from seven to ten, the four days of the first king are counted each day by itself.
The first of the four days is not completely included in time. It contains the creation of time. The creation corresponds to Brit Mila, on the tenth of Nissan. At what hour should we say this occurred? I think that there are reasons to say that this must be the hour of Mincha Ketana, 2.5 hours before the end of the day. This would add 2.5/24 times 1000 times 304805, which is 31750521 years, to the ages mentioned in the previous post, which makes the age of Universe 13748053403 years...
