Note that each individual Credit page includes currently include a <style> CSS stylesheet, and a centered <h1> title that displays "PHP 4 Credits", before the credits table(s).
So these elements will be repeated on the page if you use successively several phpcredits() calls with distinct flag values.
The embedded stylesheet may corrupt your page layout if you have another stylesheet generated before the content generated by this call. You may need to use an ob_created buffer to capture the ob_contents() after calling this function, in order to eliminate the <h1>title and the <style> CSS stylesheet.
Also, the generated HTML code only complies with HTML 4.01 or lower, but not as XHTML 1.0 (it uses deprecated attributes, and don't close empty HTML tags explicitly with />).
Note that there's no way for now to isolate the credits for a specific extension name (with CREDITS_MODULES) or for a specific SAPI module name (with CREDITS_SAPI).
The GENERAL_CREDITS displays also 2 tables: the first one is "Language Design & Concept", the second one is "PHP4 Authors Contribution" for the main PHP core subprojects (Zend Scripting Language Engine, Extension Module API, Unix Build and Modularization, Win32 Port, SAPI Abstraction Layer).