Basically this calc but with these values plugged in so we get the right result. Permission granted to do this was here

1.517x10^41 joules is the GBE for the average star

1.517x10^41 times 2,000 = 3.034x10^44

1.517x10^41 times 11,000 = 1.6687x10^45

1.517x10^41 times 20,000 = 3.034x10^45

If I failed this I am an embarrasment to VSBW and I will impale myself with an Odachi.

Buuuuuuh wait a second

Well, if you look in the comments, Azzy pointed out here, the author was kinda confused, as Globular clusters don't usually have thousands of stars, and he was probably actually referring to open clusters. So, as he hath commanded here, I'll plug in another set, 100,000 stars and 400,000 stars.

1.517x10^41 times 100,000 = 1.517x10^46

1.517x10^41 times 400,000 = 6.068x10^46

Final Tally

2,000 Stars: 3.034x10^44 Joules, or 3.034 FOE, or Large Star level (invalid due to new information from Azzy)

11,000 Stars: 1.6687^45 Joules, 16.687 FOE, Large Star level+

20,000 Stars: 3.034x10^45 Joules, 30.34 FOE, Solar System Level

100,000 Stars: 1.517x10^46 Joules, 151.7 FOE, Solar System Level

400,000 Stars: 6.068x10^46 Joules, 606.8 FOE, Solar System level

All of this done by a fodder lord of change that Khârn should be quite above.

Not that it matters since Gorechild is a thing.