Can we, really?In HD, we can now see that the bridge displays at the end of STIV do indeed say "transwarp" as per the reproductions in Mr. Scott's Guide to the Enterprise.
http://movies.trekcore.com/gallery/albums/tvhhd/tvhhd2278.jpg
Here we see a supposed "transwarp" graphic next to Nimoy's right shoulder, the same as on p.122 of Mr Scott's. The (illegible) white text below the white line at the bottom is the bit that's supposed to say "transwarp" - assuming it extends half the way into the very rightmost column of the bluish strings of numbers above. However, it does not extend that far, but only to about one-third of that column, which would be consistent with the text saying "warp subsys 525" rather than the booklet's suggested "transwarp subsys 525".
Basically, then, HD confirms that the graphics were never modified with the word "transwarp" for onscreen purposes, merely for the purposes of Mr Scott's.
Timo Saloniemi