One award explains the whole increase
World Rugby awards seven points for a penalty try, with no conversion attempted. A scoreboard jumping by seven does not require a missed camera shot of a successful kick.
Suppose a team has twelve points when a penalty try is awarded. The score becomes nineteen from that award. If the programme immediately cuts to the restart preparations, there is no missing two-point conversion to reconstruct.
Read the signal before inventing a scoring sequence
The award concerns foul play preventing a probable try or a more advantageous scoring position. It does not mean a player necessarily grounded the ball visibly. That is why searching the replay only for a touch-down can miss the reason for the decision.
Separate an ordinary try followed by a successful conversion from the single penalty-try award in a viewing log. Both can add seven, but they are different sequences. The arithmetic is identical; the event record is not. The example explains the score change rather than deciding whether any unnamed piece of foul play warranted the award.
Questions answered
Is another conversion available after a penalty try?
No.
Can two different scoring sequences each add seven?
Yes: an ordinary converted try and a penalty try.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.