Teams switching opponents and divisions. Fresh No. 1 seeds in most divisions. Several new at-large entries and an additional division.

In a matter of 19 hours late last week, the first CIF-SS girls water polo playoff brackets to follow computer-generated power ratings changed quickly and dramatically.

The section released revised brackets Saturday morning after originally introducing the postseason pairings Friday afternoon.

While the premier, eight-team Open Division remained untouched, here’s a sampling of some of the Orange County changes that illustrate the movement in advance of today’s first-round matches:

Sunny Hills and Huntington Beach shifted to Division 1 from Division 2 and received first-round matches on the road against top contenders San Clemente and Beckman, respectively, on Thursday. Sunny Hills (22-6) was originally set to be the No. 2 seed in Division 2.

El Toro (20-8) ascended to the top seed in Division 2 and replaced Temple City. In a new Division 2 pairing, Temple City (21-7) plays host to first-time league champion Buena Park (14-15) in the first round today. El Dorado (12-13) rose to the top seed in Division 5.

Esperanza (15-13), originally the top seed in Division 4, climbed to Division 3 and received a road match at Etiwanda today.

Villa Park (14-12), Portola (12-9), El Modena (15-12) and Godinez (10-6) — all of which were excluded as at-large candidates in the original playoff draw — received at-large berths in the revised brackets. In Division 3, Villa Park will travel to Chaparral today while Portola plays host to Culver City. In Division 5, El Modena plays host to Valencia in a first round match today while Godinez plays at West Covina.

The section’s original draw featured a total of six divisions — the Open Division through Division 5. In the revised edition, there are seven divisions with the addition of Division 6. It’s a change that matches the number of divisions contested in boys water polo in the fall.

The Southern Section on Saturday apologized for “any confusion” and cited two reasons for the sweeping changes: “faulty data” and an “attempt to be as fair to all member schools as possible, especially those so devastated by the many local fires.”

The faulty data related to the treatment of forfeits in the Massey computer ratings, the section stated.

“The data used to feed the computer rankings system included an algorithm that referenced National Federation of State High School Associations water polo rules on scoring forfeited games,” the section stated on Saturday.

“That rule states water polo forfeits result in a 5-0 score for the team receiving the forfeit win. To avoid skewing the resulting outcome, those games were rated at “0” for both teams by the water polo department when inputting the scores into that system. Unfortunately, that system did not render a power ranking that recognized that weighted designation.

“Thus, 5-0 wins by certain schools resulted in the system interpreting those to be 5-0 wins in the pool. Like dominoes, once those scores populated as such, they created a situation that caused all following divisions to be incorrect. Once alerted to that fact, the water polo department immediately set upon remedying that mistake.”

Los Alamitos’ late-season forfeit of eight matches was among the forfeit data, CIF-SS assistant commissioner Kristine Palle confirmed. There were also several 5-0 scores reported due to the fires, she added.

“Originally, I didn’t know until I released the initial brackets there was something terribly wrong,” Palle said Monday. “Then the phone calls and emails started. It’s natural to get some, but the volume was concerning so we had to backtrack.”

Palle praised Garden Grove coach Eric Henninger for his assistance in correcting the brackets. By rule, section playoff pairings can be changed before the first round with new information or updated results.