Google Web Versus Google AJAX API Search Results

Google search results via their API vary greatly versus the results from the web interface (as an anonymous, not-logged-in user). This has been reported by others, but here is a direct test performed by me. We are fortunate in this example that the first two results are the same (albeit in reverse order). However the next results bear no resemblance to each other whatsoever.

The default Web UI returns 10 results at a time (on a page).

The default AJAX API returns 4 results at a time, and so was repeated twice advancing by four for the second result set.

Searching for the term sample works through the AJAX API came in this order, with the order through the normal (not logged in) UI shown in parenthesis:

MLA Sample Works Cited Page - OWL - Purdue University
(2) http://owl.english.purdue.edu/owl/resource/747/12/

Sample MLA Works Cited List (Daly)
(1) http://dianahacker.com/pdfs/hacker-daly-mla-wc.pdf

Work Samples
(X) http://www.ncsu.edu/career/experience/resumes/work.php

Board for Certification of Genealogists ® - Sample Work Products
(X) http://www.bcgcertification.org/skillbuilders/worksamples.html

MCAS Student Work/Scoring Guides - Massachusetts Department of ...
(X) http://www.doe.mass.edu/mcas/student/

What is work sample? definition and meaning
(X) http://www.businessdictionary.com/definition/work-sample.html

Sample Work Rules | SME Toolkit
(X) http://www.smetoolkit.org/smetoolkit/en/content/en/1014/Sample-Work-Rules

Sample Resumes | CV Samples | Resume Examples
(X) http://www.resumeedge.com/promo/samples.shtml

Only in Web results (first page, that is, first 10):

Sample Works Cited Page
(3) www.tallmania.com/Works%20Cited%20Sample.htm

A Sample Works Cited Page - Capital Community College
(4) webster.commnet.edu/mla/sample.shtml

BizzyNate | Sample Works
(5) www.bizzynate.com/list.php

Sample Bibliography or Works Cited in MLA Style
(6) www.aresearchguide.com/sampleworks.html

Sample Works Cited - MLA Style & Citation Guide - Library at ...
(7) library.miracosta.edu/content.php?pid=151647&sid=1298276

[PDF] Sample Works Cited Entries: APA Format (6th edition) Books ...
(8) www2.ohlone.edu/org/library/APA6th.pdf

Sample Works -- Personalized Gifts wtih Your English Name ...
(9) www.usdiner.com/ChineseCalligraphy/Sample_Works1.htm

Sample WORKS CITED page. - Geocities
(10) www.geocities.com/athens/oracle/4184/WorksCited.html