Yes, premiums start to converge at further OTM, For example. XYZ at $100. Calls at 100 and 105 will have larger premium difference (say $7.5 and $4, diff of $3.5), but calls at 110 and 115 will have smaller premium difference (say $2.5 and $1, diff of $1.5). Basically further OTM is less...