Thank you for your question and also for providing an image. This was discussed with the members of the UEB Literary Committee and we have agreed that yes, you may use the lower sign in in the sequence in.);
UEB 10.5.4 explains the lower sign rule as it pertains to "enough" and "in" and states: Use the lower wordsigns for "enough" and "in" with any number of lower punctuation signs provided the sequence includes a sign with upper dots.
The abbreviation for inches is shown in your example as "in" followed by a period, which has only lower dots but is followed by a closing parenthesis which contains an upper dot. A semicolon that contains only lower dots ends the sequence. Although "in" would be a lower groupsign in the whole word "inches" it would be governed the same by the lower sign rule as a lower wordsign or lower groupsign.
In your example, the lower sign "in" (dots 35) may be used since it is in contact with the upper dot contained in the closing parenthesis.
If not for the parentheses, you would not be able to use the lower sign because the sequence would contain only lower dots.