Originally Posted by Vespobuteo
What is a bit surprising is the lower transmission of the 20-70x eye piece. Maybe coatings haven't been updated to the latest ones yet?
The 20-70x has 12 elements in 8 groups, the 30-60W 10 elements in 6 groups as per the Meopta pages, so 4 surfaces less (2 per group). This would account for one or two percent better transmission in the 30-60W with current multilayer coatings in both EPs.
Since the difference is quite a bit higher, newer coatings are probably present in the 30-60W. It's quite common for optics to be built in batches and only build a new batch when the last is sold off. With fairly low volume items like spotting scopes this might take a few years.