The official ELF Japan website has just added this information; you can also find it on the avex site as well.
Due to popular demand, an additional concert has been added!
「SUPER JUNIOR K.R.Y. SPECIAL CONCERT in JAPAN」 Additional Concert
2010.08.1 (Sunday) Tokyo International Forum Hall A
OPEN 13：00 START 14：00 (Planned)
☆Faster than anywhere else 『An additional concert! E.L.F. JAPAN concert reservations begin!』
Ticket limitations: 4 tickets per person
For additional details, please register at E.L.F-JAPAN
General sales：2010.-07.03(Saturday）at 10：00－ in ticket agencies （for both the original concert and additional concert）
Planning and production： S.M.ENTERTAINMENT JAPAN/avex live creative
For inquiries, contact Sunrise Promotion Tokyo 0570－00－3337(10.00am – 7.00pm）
News about original concert posted here by Alice
In other words, there’ll be a concert that starts at 2pm, and another one that starts at 6pm! I included the reservation details in case there are any ELFs in Japan who would like to go and have an address and credit card that they can actually reserve the tickets with.