On fiverr, I work with the context of providing the lowest possible rate for the client - which means a basic service - which doesn’t include revisions. On other sites, I charge more, so view revisions differently of course.
On fiverr, for me, a revision should be paid for either A or B.
If the client isn’t happy with the tone of the read - is that because they have asked for something in particular and you haven’t provided it (in which case - you should revise for no charge, but in my experience is a rare situation) or because they didn’t specify or were very vague about what they want and their voiceover has turned out differently to what they had in mind - which is not the VO talents fault.
Also - if there are any words that you have mispronounced - for me I often find it is business names, people names, place names, then the VO artist should ask the client to provide that information before recording and if they don’t, then they are charged for a revision. I admit, I can be a little soft with that, but it is super frustrating if someone doesn’t tell you how something should be said, then you have to completely re-do the work, because you weren’t told in the first place. Again - not the VO talent’s fault - it came from the client’s assumption you would know how they want everything in the script said/pronounced.
For B - changes to the script should always be a paid revision.
By the way - I specify my revision policy on all my gigs - in the description, in the instructions etc and I recommend that all sellers do that - as it makes it so much easier to back yourself when a client asks for a free revision or when you send them the extra request for the revision. My gigs state no revisions unless I make a mistake (which I would naturally always correct for free).
@misscrystal it is really hard to set a price in advance for a revision for a VO - as it depends on what they want changed and the scope of their original work. For example, a change on a 15 second phone greeting, is far quicker and easier to make, than completely re-doing a 5 minute voiceover because the client has now decided they want it fun and friendly when they originally asked for corporate.