SES Send-statistics incorrect - missing messages

We are a new SES user and could not find any information re:Post about this?

Have a separate incoming email server, using SES to send. Just started using SES SMTP for a month or so and starting slowly. Sending about 20-30 mails a day.

SES send statistics are inconsistent, sometimes reporting all mails sent, sometimes only 3/4 or even half i.e. send 20 mails and SES reports 17, or 15, or 10 sent. Only get about one bounce every 2 or 3 days, no complaints, rejections or any other errors or notifications. Incoming server replicates all mails sent in the sent folder. Historic bounce rate >0.1%.

Are the missing (not reported) mails being sent? Cannot find a way to check this on the SES platform.

All mails are sent by hand, using MS Outlook from a single IMAP account. 95% of mails are very similar, HTML formatted ~100 words, link button, unsubscribe link and contact details ~60kb total. Each mail has a single customized line of text, name, company and picture.

Any help or pointers to troubleshoot are greatly appreciated. Thanks