I used to have that issue with teething, ds would wake at 145 when he was usually having 3 hours naps. I would go at 130 mark (you should go at the 115) and stay silent in the rocking chair, waiting for a jolt or something that would indicate me he'd wake. It was usually that he'd jump from deeply sleep to seated so if i did WTS i would wake him at all and there was no turning back. Instead, i'd wait for the first jolt (i became an expert and i started noticing when his breathing would change right before the jolt) and start shshing a lullaby (which used to soothe him back then when he was a newborn). Sometimes i would pat/shs depending on his upsetting. It took me a week before i would remove myself from the bedroom at the 130 mark. He continued to scream in his sleep at 145 but would put himself back to sleep. A week later, he started sleeping through that mark too.
HTH!
