[Paraview] Clipping Range

[the lily]

Hi everyone 
I'm trying to understand the way that paraview is using to calculate the clipping range 
I used the can and disk data that on Paraview's website 
I found out that when I render each one of them separately I get the following clipping range 
Clipping Range for disk[25.487748091436124, 61.463879508713894]Clipping Range for can  [26.225040075556972, 83.75794649703468]
but when I render both of them in the same scen I get the following 
[17.002656175488287, 88.36913844706902] 		 	   		  
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