What is the value of King Tusks ivory comparatively speaking ?

The Edward Donkin tusks, dated 1928, which measured 6' 9.8" were purchased Nov. 28, 2006 for $39,435.00
A pair of African bull elephant tusks, dated 1983, which measured 6' 2.1" and 6' 8.3" were purchased Oct. 11, 2006 for $21,600.00

I am assuming that the Edward Donkin tusks, which are close to the same size, sold for more then the African tusks for a number of reasons. The provenance of being the Edward Donkin tusks, the equal length of the tusks, the age of the tusks, and they were Asian tusks.

The world’s biggest pair of tusks are owned by Queen Elisabeth II and are on permanent display at the Victoria and Albert Museum in London. The second largest are privately owned and are part of the famous Powell-Cotton collection in Kent.

The third largest pair at 9' and 8' 9.2" were purchased Dec. 19, 2005 for $637,640.00 with the provenance: "The elephant was shot in 1970 in Tanzania by a local ivory hunter who was himself shot. The tusks were seized by the Tanzanian government and, the following year, they were sent to a Safari Club International meeting in Budapest where they were checked and recorded by leading authority Rowland Ward. The tusks were found in the cellar of an old piano-manufacturing business in the Borders and had been bought many years previously for the manufacture of piano keys."

Given the value of a set of tusks is dependant on age/equal length/provenance, what would 57(age) King Tusks(provenance) ivory at 7' 0'' and 6' 6"(unequal length) be worth today, comparatively speaking?