Hadn't thought of that. My first impression was having sent off this roll (Delta 100) and a roll of Delta 400 together, the lab had developed them both for 400 - i.e. 24C for 9 mins, where Delta 100 would be 18C for 6 mins. The roll of 400 came out fine.
EDIT: Oh, I see what you mean by 'lines'. They are in fact telephone wires. I'm referring to the sky, yes.