Internal Search wrong numbers

Hello,
(please excuse my bad english its not my native language)
I have saved a long time ago what people search on my website.
Now i wanted to import all the data to Piwik. For that i have written a script with a cron job that send all data via API setForceVisitDateTime(time); and doTrackSiteSearch(search, category, count hits); to Piwik.
Now I noticed that in Piwik all datas are wrong when i look for the whole year. Could it be that Piwik only get some of the newest keywords and dont get all?
Or could it happen that I overstrain Piwik with all that data?

Thanks

after importing old data you must tell piwik to re-process old archives with: How to - Analytics Platform - Matomo