Unfortunatly relying on secondary sources for the development of french artillery under Napoleon does not give the whole picture and is unreliable.
Your statement that AnXI only had two guns is a rather over simplification of the fact. The AnXI 12-pdr 6-pdr and howitzer were produced in large numbers. I have casting returns for at least 1000 AnXi 12-pdrs. The guard artillery were equipped solely with AnXI guns. In 1809 all foreign guns and none AnXi guns were removed from the army of Germany. 90% of the guns used in 1813 were of AnXI types.
In addition at least 200 of the new 24-pdr siege guns were cast, the AnXI mountain equipment was also put into service in 1809 in the tyrol.
Saski is a nice secondary source but lacks the clarity and detail of the actual archival material held in France. The AnXI artillery system has been virtually written out of the Napoleonic epoch by secondary and tertiary authors mainly because it was devisive and opposed by the 'old guard' of artillery officers and the whim of the new royalist government in 1814 and 1815 who wanted to return france to its state pre 1789.
I argue that reading the french archives, napoleons correspondance, catalogues of extant gun tubes says a very different story.
The problem however, is until my research is published, it can easily be deried as no one has ever seen what I say in print. You claim no tests were done. Two set of tests were run on the new tubes to ascertain the weight of metal for the new tubes, lenght of bore and effectiveness at Vincennes and Strasbourg from the back end of 1801 through most of 1802. 12months of tests I admit is not the same as field evaluation, but these guns were tested, and modified in 1807 as a result of there short comings in the campagin of 1805-1806.
The files at SHAT 2w 84 casting artillery, the notes of the artillery committee and correspondance and test results are pretty clear.The report of general ruty, tests carried out in 1819. Valee tested the AnXi guns as opposed to the Gribeauval guns for his new system of artillery. If one looks at original sources, not 90% of printed books, the information for AnXI is abundant.