To be Penvose or to be Penrose

[Chris Penrose]

I am helping a would-be relative in Texas who is descended from a John Penvose of Tywardreath - according to various sources. After looking at original transcripts on CD and film, I am of the opinion that the name "Penvose" originates as a result of lazy writing - a stretched 'r'. No offence intended to anyone, including the transcribers who produced the Phillimores and various town and parish clerks.

The transcripts of the 1841 census, where there should be Penvoses, seems to indicate modern transcribers believe this too. There are numerous records on FHOnline, LDS, and other sources which need eliminating/adjusting if this is true.
Can anyone help me clear this up?/Is anyone else brave enough to tackle this head-on?