This is an attempt in explaining how boost and turbo timings interact at various stages in acceleration.
I will give various examples to show how the settings affect how boost and turbo timings are added.
These are just meant for illustrative purposes, they do not reflect how timing is actually added.

[<-------------------------Total 64 steps of timing--------------------->]

1) Boost: 44
Turbo: 20
Turbo delay: 0.3s
Car on start of straight, full throttle applied.

At 0.2s:
[####### 30 boost #######-----------------------------------------]
At 0.3s: turbo kicks in, max turbo slope
[####### 30 boost ####### ******20 turbo******-----------------]
At 0.5s: All timing added
[####### 30 boost ####### ******20 turbo******###14 boost###]


2) Boost: 44
Turbo: 30
Turbo delay: 0.3s

At 0.2s:
[####### 30 boost #######-----------------------------------------]
At 0.3s: turbo kicks in, max turbo slope
[####### 30 boost ####### **********30 turbo********---------]
At 0.5s: All timing added.
[####### 30 boost ####### **********30 turbo********#4boost#]
Note: only 34 steps of boost used. total steps= 64


3) Boost: 50
Turbo: 20
Turbo delay: 0.6s

At 0.2s:
[####### 30 boost #######-----------------------------------------]
At 0.5s:
[############### 50 boost ###############------------------]
At 0.6s: turbo added
[############### 50 boost ###############***14 turbo*****]
Note: only 14 steps of turbo added. total steps=64


This is how I think the timing is added. I could be way wrong, if so, please correct me! If i'm right, i hope it helps you visualise better

hth
zipp