This is one of the boring, get paid month after month, type of trusts. Although the annual report probably estimates the reserves will last a decade, I expect them to last much longer. Just try to get the best buy in price you can and collect monthly distributions for a few decades. About 2/3 oil, 1/3 gas, but the gas must be wet gas as they get paid much more than NYMEX prices for it (see the prices received in each distribution announcement). No hedging so fully exposed to oil/gas prices on both the up and down sides.
I guess we only know what it says in the 10Q. During Q2 approx 18 million was distributed by the trust; so 5 mill represents a little less than a month's distribution which will be spread the next 12 months so WORST CASE we may see a little less (perhaps the distibution lowered a penny each month for 12 months).
Looks like they are withholding it all at once. Big drop in this month's distribution due to all royalties from one property being withheld. It doesn't cover the full claimed overpayment so likely next month's distribution would be lower too.