So far you guys are missing a big hint that USS IOWA was being painted ... maybe pattern revised ... while at anchor here.
In the series of images (80-GK-1613, 1614, and 1615) taken during the boxing match on 27 May 1944, note that the aft fire control tower is painted with the starboard half painted 5-N and the portside painted 5-H. The same way it was during January 1944 images.
Another image (cropped) taken during the boxing match, 80-GK-1614. A little sharper than 80-GK-1613.
However, in the image (80-GK-14182) taken during church services, note that the same tower has been painted 5-N on both sides.
The envelops at NARA that the original transparencies are in have dates that almost always are NOT accurate. The dates likely reflect when they arrived at the USN Photo Center (NPC). Ships during WWII didn't have the ability to process color transparencies and the film had to be sent to where it could be. I don't know if they could process at Pearl Harbor by 1944, or if the film had to go stateside. I was able to date the three "boxing match" images via the ships involved and the match itself, specifically the destroyer alongside the portside and the oiler on her starboard side. So the date of 27 May 1944 is a pretty solid point as to what the tower looked like at that point.
I couldn't date the church services image, because of a lack of clues, since church services were a common occurrence. It looked like USS IOWA was at anchor. I had and still wonder if the church services photo was taken by the same photographer shortly AFTER the boxing match. The original transparency envelope has a date of "about June 1944", which seemed to make that a possibility. 27 May 1944 was a Saturday, so quite possibly the church services photo was taken on Sunday 28 May 1944.
Back to the Church Services image (80-GK-14182). Note several things that point to painting is or was in the process of being done. Note the sailor under the middle 16-in gun of turret #3, he looks like he is painting that barrel. The paint on the gun barrels and the turret itself appear much fresher than many other areas. Also, look at the Main Gun Fire Control Director, the front of the director turned towards starboard looks like it hasn't all been repainted with areas of 5-H still visible. Further, there is another sailor working on the aft Mk 37 director ... painting? The aft stack appears to be faded and exhibits areas that had been touched up in the past. Compare to the searchlight platform in fresh new paint. Also, as had been pointed out, the areas of lighter paint is noticeably so compared to the 5-H paint next to them. But, note that in a couple of those places (forward stack) the demarcation line if jagged, not a sharp line.
The lighter paint could be fresh paint not yet fully dried or a "barrier" coat before 5-H or 5-N is applied.
The thing about camo paint during WWII, a photo taken one day can show one pattern/scheme and a photo taken a few days later can show something completely different. For whatever reason, the dazzle pattern on USS IOWA was altered and apparently several times during 1944.