The two flags on page 273 of the book - 32nd Alabama and Austin's LA Battalion are indeed from the same maker - Jakcson Belknap - as are the other flags of this Second National issue - ALL of which have the same characteristics.
The difference between Howie's book from the mid-1970's and the FOTC website is growth in knowledge and that he went back and took second looks at a lot of these flags. That book, while truly ground-breaking and still loaded with viable information, is also way out of date based on a lot of things that flag historians have found since it came out.
One of the "new" things is Jackson Belknap, who I found in the Citizen's & Business files at the National Archives along with a ton of flag making invoices. He lived in Mobile and he and his wife Sarah both made lots of flags.