amespace prefix = o ns = "urn
I believe you are both measuring the same thing. Based upon my experience with the testing kits, your reading of .4 ish is about 4.0 g/l. The kits are measuring a percent of concentration (0.4%).
There can be a number of reasons for the different readings. First, the university extension service may have used a pH meter to determine the end point rather than the color solution. The color change at the end point for a red wine is difficult to see. With a pH meter, sodium hydroxide is slowly added until the meter reads 8.2 and you are at the end point.
Second, finished wines have a lower acid level than the juice. The fermentation process can reduce the acid by 0.5 to 1.0 g/l. If the wine had gone through malolactic fermentation, an additional reduction of 0.5 to 2.0 g/l or more could have occurred.
To determine the end point in a red wine you might want to try the “white tile” method described in this article: http://www.vawa.net/articles/acid1.shtml
I have never been confident in my ability to see the end point.