Nicholas (and Lisa Ann),
Fairly common pattern. There is likely some polymorphism (at least) in the enzymes supporting glycolic. This would have to be tested out from the GPL1000 SNP Profile, but I often see Glycolic elevated more than Glyceric. The Arabinose in the sample you provided adds a little to the oxalate level, but not likely as much as the endogenous production (and dietary intake).
I will be attended a seminar on polymorphism testing in a few weeks and hope to gain more insight into these varied issues.
Sincerely,
Dr. Woeller