Fail to show different plots in the same loop by using U8glib library

I've been trying to show 2 plots in the same loop on a LCD by using the U8glib library but it fails.

The reason that the plots has to be presented sequentially in the same loop is I am showing an averaged value and FFT result from an analog pin, and whenever the loop update it would pick a new measurement.

I was trying to write the program as the way below, however, it is apparently one of the programming restriction in the library and I would like to ask how can I do the same thing without updating to the new loop?

show plot A
delay 5s
show plot B

Information of LCD and library can be found below: Used LCD: LM6059, 128x64, Adafruit Controller: ST7565 GLib: U8glib

Many thanks!