Members of the state Reapportionment Commission are giving themselves more time to study a revised plan for staggering the terms for new state Senate districts so that about half come up for re-election every two years.

Commissioners, convening in a special meeting Wednesday, decided to recess until next Thursday to study new information and any available case law for guidance. They also are seeking greater participation, since only five of the nine commission members were present Wednesday.

The commission still must take a final vote on the revised list of staggered Senate terms.

The issue of staggered terms was thought to be decided last week, when commissioners voted to approve new district boundaries for federal and state offices. A mistake in the formula for staggering the Senate terms was discovered later, affecting two districts.

At Monday’s meeting, to approve the revised list of staggered terms, it was discovered that an additional error further affected the formula used to determine which seats would be up for two-year terms next year and which would be up for two-year terms in 2016.

New terms are set based on a mathematical formula, previously approved by voters, that determines how many residents in a new Senate district did not vote for Senate in the last election. The 12 new districts with the fewest number of such voters are the districts that would be up for two-year terms in 2012.

Under the latest revised plan, presented Monday, two-year terms in 2012 are set for districts 1, 3, 5, 6, 7, 12, 16, 17, 18, 21, 22 and 23.

Originally, districts 7 and 22 were listed as a four-year terms and districts 11 and 24 as two-year terms. The latest plan reverses those term lengths.