There is confusion in understanding investment materials - promoted and caused by books and articles and by postings !
It caused me multiple failures years ago, and I commend aonemarine for pointing it out.
Pay attention Folks !
The misnomer is the word "Burnout"
Please know this , Raising the Temperature to 700 C or 1300 F is to cure the investment !
It has NOTHING to do with melt out,burnout, ash point or whatever your pattern is made of.
I lost over 6 months on a project and learned that the books and youtube are wrong for using that term.
Yes it is good to know at what temp your pattern material (wax,PLA ect) melts or sublimates or burns, but know the investment has other requirements for curing and to prevent cracking with heating - otherwise failure is in the cards !
Rich