Half way through a customized plan and did half Monty today. Thanks to a great plan written by sir spencer I saw some significant improvement in my FTP and MAP.
My question is, should I now be scared about erg mode workouts with my new numbers! Particularly the long scream! It was a challenge before, I’m thinking it’ll be even more of a challenge now!!!
Yes!
However, trust the numbers and more so: Trust yourself 
“It never gets easier you just get faster – Greg LeMond” (however pretty sure he stole that quote from GvA 
)
Why should you be scared?
Since you have proportionally more fitness, higher targets should result in a similar challenge as before. Greg LeMond’s famous quote said it never gets easier. He never said it gets harder. Aspects of your external performance (speed, ability to climb, etc.) are now better.
Being fearful will, for sure, interfere with your performance.