That's actually no longer true. As I noted in another thread, the VA has issued a statement regarding the restoration of post 9/11 benefits. As it currently stands, using chapter 31 does not eat into your GI bill, though it seems using your GI bill will eat into your Ch 31 benefits.
changes to the policy on restoration/entitlement use (regarding restoration of Post9/11 months used for Chapter 31) ***General Council Memo Procedural Advisory 48 month rule and chapter 31 entitlement use for original claims dtd. 12-10-2015 "Title 38, United States Code, a Regional Office had misinterpreted the 48-month rule. GC held that the use of benefits under 38 U.S.C. chapter 31 does not limit the use of education benefits listed in 38 U.S.C. § 3695(a). However, use of educational benefits listed in section 3695(a) could limit the number of months of assistance to which a service-disabled veteran may be entitled under chapter 31". This info is given out by the Post9/11 info number. 1-888-442-4551 (1 888 GI BILL 1) from 7AM - 7PM Central Time
That info was actually posted on the Ch. 31 FB group that Ben Krause (the author of the article you linked) founded and still admins.