Yes, RuleORama was envisioned for smaller grammars than the stock OpenEars grammar tool can handle due to the fact that it provides more speed. This one has > 800 potential utterances so it isn’t a small grammar for RuleORama.
It might work better as a stock OpenEars grammar assuming that you change it so that the numbers equal to and greater than 20 are formed with a rule declaring the base 10 number (i.e.”20″) followed by the numbers 1-9, which lets you avoid a single rule with 100 entries.